Using options.email for svn credential is not a good idea.

It breaks the use case when a dev outside corp wants to send a job's email to someone else.

Review URL: http://codereview.chromium.org/558062

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@37644 0039d316-1c4b-4281-b951-d872f2087c98

trychange.py

@@ -334,8 +334,6 @@ def _SendChangeSVN(options):
     try:
       command = ['svn', 'checkout', '--depth', 'empty', '-q',
                  options.svn_repo, temp_dir]
-      if options.email:
-        command.extend(['--username', options.email])
       gclient_utils.CheckCall(command)
 
       # TODO(maruel): Use a subdirectory per user?