test-rm: fix regexes to handle newer *and* older git

To accommodate optional lines, we need to use a construct like this:

  foo(
  bar)?

instead of this:

  foo
  (bar)?

The problem became apparent when people tested against older git after
the introduction of the patch to work with newer git:
292361d86d1cf0cc555681ae43371d66c8ebb366

Thanks to Greg Troxel and Basil Mohamed Gohar for reporting the
problem.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>