Clear existing Change-Ids from description if issue is 0

git cl upload may not create a new change even if issue is 0 because
of a leftover Change-Id footer in the commit message.

Bug: 1484251
Change-Id: Ibee0542e0f5a2cbf930b1882892fbb7640054b69
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4880971
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
diff --git a/git_cl.py b/git_cl.py
index d1936ec..cfb6234 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -1788,6 +1788,12 @@
         bug = options.bug
         fixed = options.fixed
         if not self.GetIssue():
+            # There isn't any issue attached, so we shouldn't keep existing
+            # Change-Ids in the description.
+            if git_footers.get_footer_change_id(description):
+                description = git_footers.remove_footer(description,
+                                                        'Change-Id')
+
             # Extract bug number from branch name, but only if issue is being
             # created. It must start with bug or fix, followed by _ or - and
             # number. Optionally, it may contain _ or - after number with
@@ -1829,7 +1835,7 @@
     def _GetTitleForUpload(self, options, multi_change_upload=False):
         # type: (optparse.Values, Optional[bool]) -> str
 
-        # Getting titles for multipl commits is not supported so we return the
+        # Getting titles for multiple commits is not supported so we return the
         # default.
         if not options.squash or multi_change_upload or options.title:
             return options.title