Moved tests for commit -o option to own test class

Moved tests for commit -o option to own test class

We test the -o option of the commit command very accurate by
writing tests for each line of a decision table. In order to
still be able to point new jgit users to the CommitAndLogCommandTest
to find out how to use log() and commit() I factored out these 1200
lines of very specific tests into their own class.

Change-Id: Icf7c517f790a8fa79c8afd9b7f4a2805cf79196e
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>