Commit indexing fails to index commits on repositories with very large commit histories

For some very large repositories, commit indexing does not index newly added commits. The commit indexing starts a git process to determine added and removed, but only waits up to 5 seconds for it to return the first commit. If no commit is found within those 5 seconds, the commit indexing aborts and does not try to index those commits again.

On some very large repositories, it can take longer for the git command to return the first commit, and this leads to commits not being indexed. 

The 5s timeout is a bit aggressive and should be increased. In addition a configuration property should be introduced to allow the timeout to be overridden without code changes.