Merge branch 'sk/t1100-modernize'

The test script 't/t1100-commit-tree-options.sh' has been modernized
by converting test cases to the modern style (using single quotes and
tab indentation) and moving the creation of the expected file inside
the setup test so it runs under the protection of the test harness.

* sk/t1100-modernize:
  t1100: move creation of expected output into setup test
  t1100: modernize test style