Workaround a git clone bug on Windows.

On Windows "git clone url path/repo" does not create 'path' if it does
not exist. It fails with:

Fatal: could not create work tree dir 'path\repo'.: No such file or directory

this patch manually creates the subdir if it does not exist.
Review URL: http://codereview.chromium.org/7080063

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@87522 0039d316-1c4b-4281-b951-d872f2087c98

gclient_scm.py

@@ -493,6 +493,12 @@ class GitWrapper(SCMWrapper):
       clone_cmd.append('--verbose')
     clone_cmd.extend([url, self.checkout_path])
 
+    # If the parent directory does not exist, Git clone on Windows will not
+    # create it, so we need to do it manually.
+    parent_dir = os.path.dirname(self.checkout_path)
+    if not os.path.exists(parent_dir):
+      os.makedirs(parent_dir)
+
     for _ in range(3):
       try:
         self._Run(clone_cmd, options, cwd=self._root_dir)