Remove --shallow from git cache call in gclient

We don't want to do a shallow clone into the cache because it is not supported
on versions of git older than 1.9.

BUG=261741

Review URL: https://codereview.chromium.org/198103012

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@257578 0039d316-1c4b-4281-b951-d872f2087c98

gclient_scm.py

@@ -681,8 +681,7 @@ class GitWrapper(SCMWrapper):
     if not self.cache_dir:
       return url
     v = ['-v'] if options.verbose else []
-    self._Run(['cache', 'populate'] + v +
-              ['--shallow', '--cache-dir', self.cache_dir, url],
+    self._Run(['cache', 'populate'] + v + ['--cache-dir', self.cache_dir, url],
               options, cwd=self._root_dir, retry=True)
     return self._Run(['cache', 'exists', '--cache-dir', self.cache_dir, url],
                      options, cwd=self._root_dir, ).strip()