[bug] init be log file length when restart be

[songenjie]

issue

int fd = open(filename, O_WRONLY | O_CREAT /* | O_EXCL */ | O_APPEND, 0664); 
fdopen(fd, "ra") 

view

*** Aborted at 1590044592 (unix time) try "date -d @1590044592" if you are using GNU date ***
PC: @     0x7f0fa14679ec __GI_fseek
*** SIGSEGV (@0x0) received by PID 79596 (TID 0x7f0fa22ed580) from PID 0; stack trace: ***
    @     0x7f0fa1429670 (unknown)
    @     0x7f0fa14679ec __GI_fseek
    @          0x23775e1 google::(anonymous namespace)::LogFileObject::Write()
    @          0x23730a4 google::LogMessage::SendToLog()
    @          0x23706d4 google::LogMessage::Flush()
    @          0x2370931 google::LogMessage::~LogMessage()
    @           0xdc3eb4 doris::init_daemon()
    @           0xc4eec7 main
    @     0x7f0fa1415b15 __libc_start_main
    @           0xda72d3 (unknown)

fix

use fopen

[chaoyli]

It's better to create a issue to describe the bug which cause it.

[songenjie]

#3593

[chaoyli]

You can add another better case to test it.

[chaoyli]

LGTM