git-svn: fix buggy regular expression usage in several places
git-svn: fix buggy regular expression usage in several places

I incorrectly used $path/? and $path/* to strip off leading
directories, but places where $path = 'branches/0.17' would
incorrectly strip changes to 'branches/0.17.1' as well.

For globs, we require that our '*' is its own path component
(surrounded by '/' or nothing).  Enforce this when --prefix= is
passed to us, too.

Signed-off-by: Eric Wong <8c2951295f8292b0c03727bc4652981172298eae@yhbt.net>

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