[release] Fix release script.

Fix after https://codereview.chromium.org/1887583002/

TBR=hablich@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1881163003

Cr-Commit-Position: refs/heads/master@{#35441}

tools/release/create_release.py

@@ -239,8 +239,8 @@ class FixBrokenTag(Step):
       pass
     if commit:
       print "Found %s. Trying to repair tag and bail out." % self["version"]
-      self.step.Git("tag %s %s" % (self["version"], commit))
-      self.step.Git("push origin %s" % self["version"])
+      self.Git("tag %s %s" % (self["version"], commit))
+      self.Git("push origin %s" % self["version"])
       return True