git-cl: Set CC from watchlists only on first upload

This will prevent moving reviewers to cc when uploading patches.

Bug: 1010499
Change-Id: Ida16a4686f46350ba009bdaec1542895208c3f2d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1835016
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Anthony Polito <apolito@google.com>
diff --git a/git_cl.py b/git_cl.py
index a85226f..30088cc 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -2540,11 +2540,12 @@
                                    options.add_owners_to, change)
 
     reviewers = sorted(change_desc.get_reviewers())
-    # Add cc's from the CC_LIST and --cc flag (if any).
-    if not options.private and not options.no_autocc:
+    cc = []
+    # Add CCs from WATCHLISTS and rietveld.cc git config unless this is
+    # the initial upload, the CL is private, or auto-CCing has ben disabled.
+    if not (self.GetIssue() or options.private or options.no_autocc):
       cc = self.GetCCList().split(',')
-    else:
-      cc = []
+    # Add cc's from the --cc flag.
     if options.cc:
       cc.extend(options.cc)
     cc = filter(None, [email.strip() for email in cc])