contrib/git-svn: avoid re-reading the repository uuid, it never changes
contrib/git-svn: avoid re-reading the repository uuid, it never changes

If it does change, we're screwed anyways as SVN will refuse to
commit or update.  We also never access more than one SVN
repository per-invocation, so we can store it as a global, too.

Signed-off-by: Eric Wong <8c2951295f8292b0c03727bc4652981172298eae@yhbt.net>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

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