Fixes to roll_deps for the bots

The bots are running an older version of git which does not support the
-q/--quiet flag for branch or the --short flag for symbolic-ref.

BUG=
R=halcanary@google.com

Review URL: https://codereview.chromium.org/134723002

git-svn-id: http://skia.googlecode.com/svn/trunk@13030 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/roll_deps.py b/tools/roll_deps.py
index 2f98fb5..10822f4 100755
--- a/tools/roll_deps.py
+++ b/tools/roll_deps.py
@@ -577,8 +577,8 @@
         if self._stash:
             vsp.check_call([git, 'stash', 'save'])
         try:
-            self._original_branch = vsp.strip_output(
-                [git, 'symbolic-ref', '--short', 'HEAD'])
+            full_branch = vsp.strip_output([git, 'symbolic-ref', 'HEAD'])
+            self._original_branch = full_branch.split('/')[-1]
         except (subprocess.CalledProcessError,):
             self._original_branch = vsp.strip_output(
                 [git, 'rev-parse', 'HEAD'])
@@ -588,7 +588,7 @@
 
         if branch_exists(self._branch_name):
             vsp.check_call([git, 'checkout', '-q', 'master'])
-            vsp.check_call([git, 'branch', '-q', '-D', self._branch_name])
+            vsp.check_call([git, 'branch', '-D', self._branch_name])
 
         vsp.check_call(
             [git, 'checkout', '-q', '-b', self._branch_name, 'origin/master'])
@@ -632,7 +632,7 @@
         vsp.check_call([git, 'checkout', '-q', self._original_branch])
 
         if self._config.default_branch_name == self._branch_name:
-            vsp.check_call([git, 'branch', '-q', '-D', self._branch_name])
+            vsp.check_call([git, 'branch', '-D', self._branch_name])
         if self._stash:
             vsp.check_call([git, 'stash', 'pop'])