getPhoneLogs on device (version < android M) crashes

[dolanor]

Hi,
New to flutter, I wanted to access the call log and discovered that repo.

The problem I found was that getPhoneLogs access the permission API (available in android M) to check the permission. On a device with a version lower than that, it crashes. (log below)

I fixed it with a SDK check before calling a function with permission API, and one without permission API to be able to be called from older version.
I'll send some PR if that's ok.

E/flutter (11916): [ERROR:flutter/shell/platform/android/platform_view_android_jni.cc(40)] java.lang.NoSuchMethodError: No virtual method checkSelfPermission(Ljava/lang/String;)I in class Landroid/app/Activity; or its super classes (declaration of 'android.app.Activity' appears in /system/framework/framework.jar:classes2.dex)
E/flutter (11916): 	at com.jiajiabingcheng.phonelog.PhoneLogPlugin.fetchCallRecords(PhoneLogPlugin.java:146)
E/flutter (11916): 	at com.jiajiabingcheng.phonelog.PhoneLogPlugin.onMethodCall(PhoneLogPlugin.java:58)
E/flutter (11916): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:201)
E/flutter (11916): 	at io.flutter.view.FlutterNativeView$PlatformMessageHandlerImpl.handleMessageFromDart(FlutterNativeView.java:188)
E/flutter (11916): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:202)
E/flutter (11916): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/flutter (11916): 	at android.os.MessageQueue.next(MessageQueue.java:143)
E/flutter (11916): 	at android.os.Looper.loop(Looper.java:130)
E/flutter (11916): 	at android.app.ActivityThread.main(ActivityThread.java:5834)
E/flutter (11916): 	at java.lang.reflect.Method.invoke(Native Method)
E/flutter (11916): 	at java.lang.reflect.Method.invoke(Method.java:372)
E/flutter (11916): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1388)
E/flutter (11916): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
E/flutter (11916): 
F/flutter (11916): [FATAL:flutter/shell/platform/android/platform_view_android_jni.cc(77)] Check failed: CheckException(env). 
F/libc    (11916): Fatal signal 6 (SIGABRT), code -6 in tid 11916 (.example.regord)
*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
Build fingerprint: 'samsung/kltexx/klte:5.0/LRX21T/G900FXXU1BNL9:user/release-keys'
Revision: '14'
ABI: 'arm'
pid: 11916, tid: 11916, name: .example.regord  >>> com.example.regord <<<
signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
Abort message: '[FATAL:flutter/shell/platform/android/platform_view_android_jni.cc(77)] Check failed: CheckException(env). 
'
    r0 00000000  r1 00002e8c  r2 00000006  r3 00000000
    r4 b6f1e114  r5 00000006  r6 0000000b  r7 0000010c
    r8 bef48c94  r9 00000008  sl 00000001  fp aeda3388
    ip 00002e8c  sp bef48b78  lr b6ea7fd5  pc b6ecb978  cpsr 600d0010
backtrace:
    #00 pc 00037978  /system/lib/libc.so (tgkill+12)
    #01 pc 00013fd1  /system/lib/libc.so (pthread_kill+52)
    #02 pc 00014bef  /system/lib/libc.so (raise+10)
    #03 pc 00011531  /system/lib/libc.so (__libc_android_abort+36)
    #04 pc 0000fcbc  /system/lib/libc.so (abort+4)
    #05 pc 0002ebb7  /data/app/com.example.regord-1/lib/arm/libflutter.so
    #06 pc 000252e5  /data/app/com.example.regord-1/lib/arm/libflutter.so
    #07 pc 00024745  /data/app/com.example.regord-1/lib/arm/libflutter.so
    #08 pc 00055849  /data/app/com.example.regord-1/lib/arm/libflutter.so
    #09 pc 0002fd99  /data/app/com.example.regord-1/lib/arm/libflutter.so
    #10 pc 00031295  /data/app/com.example.regord-1/lib/arm/libflutter.so
    #11 pc 0001030f  /system/lib/libutils.so (android::SimpleLooperCallback::handleEvent(int, int, void*)+10)
    #12 pc 00010f6f  /system/lib/libutils.so (android::Looper::pollInner(int)+482)
    #13 pc 00011019  /system/lib/libutils.so (android::Looper::pollOnce(int, int*, int*, void**)+92)
    #14 pc 00083079  /system/lib/libandroid_runtime.so (android::NativeMessageQueue::pollOnce(_JNIEnv*, int)+22)
    #15 pc 000b2397  /system/framework/arm/boot.oat