Ready: Fix Null Pointer exception in #656.

[alexmoore]

Fixes Null Pointer exception for #656, do some cleanup surrounding $bucket & $key indices.

[dbyron0]

Up on line 331 above, there's another call to await with a timeout. This is the only place I can find left in the code (there are a few in the tests too) that calls await with a timeout but ignores the return value. Because it checks isDone afterwards, ignoring the return value does seem OK, though perhaps a comment would help.

For what it's worth, the test code ignores the return value here:

https://github.com/basho/riak-java-client/blob/expand-coverage-api/src/test/java/com/basho/riak/client/api/commands/itest/ITestMultiDelete.java#L40

https://github.com/basho/riak-java-client/blob/expand-coverage-api/src/test/java/com/basho/riak/client/core/operations/itest/ITestListBucketsOperation.java#L159

https://github.com/basho/riak-java-client/blob/expand-coverage-api/src/test/java/com/basho/riak/client/core/operations/itest/ITestListKeysOperation.java#L177

[alexmoore]

@srgg Getting 2 errors with the latest commits:

Running com.basho.riak.client.api.commands.indexes.itest.ITestFullBucketRead
Tests run: 5, Failures: 0, Errors: 2, Skipped: 0, Time elapsed: 2.063 sec <<< FAILURE! - in com.basho.riak.client.api.commands.indexes.itest.ITestFullBucketRead
readPlainTextValues(com.basho.riak.client.api.commands.indexes.itest.ITestFullBucketRead)  Time elapsed: 0.004 sec  <<< ERROR!
java.lang.IllegalArgumentException: An index key or range or coverageContext must be supplied
        at com.basho.riak.client.api.commands.indexes.itest.ITestFullBucketRead.readPlainTextValues(ITestFullBucketRead.java:103)

readPlainTextValuesWithReturnBody(com.basho.riak.client.api.commands.indexes.itest.ITestFullBucketRead)  Time elapsed: 0 sec  <<< ERROR!
java.lang.IllegalArgumentException: An index key or range or coverageContext must be supplied
        at com.basho.riak.client.api.commands.indexes.itest.ITestFullBucketRead.readPlainTextValuesWithReturnBody(ITestFullBucketRead.java:126)

I think we still need the bucket name provided in the match parameter to make a correct 2i query, even with a coverage context.

[alexmoore]

We can't let the match value be null: [set null], [throw error on null].