t9903: add extra tests for bash.showDirtyState
t9903: add extra tests for bash.showDirtyState

Add 3 extra tests for the bash.showDirtyState config option; the
tests now cover all combinations of the shell var being set/unset
and the config option being missing/enabled/disabled, given a dirty
file.

Signed-off-by: Martin Erik Werner <f1bdc424ffcfdeb5aeb2aebae202480d3984cbaf@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git