Merge branch 'fix'

* fix:
Document --short and --git-dir in git-rev-parse(1)
git-rev-parse: Fix --short= option parsing
Prevent git-upload-pack segfault if object cannot be found
Abstract test_create_repo out for use in tests.
Trap exit to clean up created directory if clone fails.

diff --cc rev-parse.c
Simple merge

diff --cc sha1_file.c
Simple merge