Minor fixes for update_git_repo.py.

 Now it catches errors (or Ctrl-C) and cleans up the g4 client.
 It also runs git commands with -v flag to capture the verbose output for
 debugging.

  Testing:
  It still doesn't have the final repository information. I tested it locally
  with a locally created repository.

PRESUBMIT=passed
R=raymes,bjanakiraman
DELTA=90  (68 added, 1 deleted, 21 changed)
OCL=45201-p2
RCL=45204-p2
RDATE=2010/11/12 19:24:21


P4 change: 42605802
1 file changed
tree: 81e2a1d0c31bcbe56697edc92efbf5806c80f620
  1. .git5_specs/
  2. v14/