Convert prompt answers to lower case before checking

When prompting for yes/no answers, convert the answer to lower
case before comparing.  This makes it easier to catch answers
like "Yes", "yes", and "YES" with a comparison only for "yes".

Change-Id: I06da8281cec81a7438ebb46ddaf3344d12abe1eb

subcmds/init.py

@@ -248,7 +248,7 @@ to update the working directory files.
       print ''
       print 'Your identity is: %s <%s>' % (name, email)
       sys.stdout.write('is this correct [y/N]? ')
-      a = sys.stdin.readline().strip()
+      a = sys.stdin.readline().strip().lower()
       if a in ('yes', 'y', 't', 'true'):
         break
 

subcmds/upload.py

@@ -186,8 +186,8 @@ Gerrit Code Review:  http://code.google.com/p/gerrit/
         print '         %s' % commit
 
       sys.stdout.write('to %s (y/N)? ' % remote.review)
-      answer = sys.stdin.readline().strip()
-      answer = answer in ('y', 'Y', 'yes', '1', 'true', 't')
+      answer = sys.stdin.readline().strip().lower()
+      answer = answer in ('y', 'yes', '1', 'true', 't')
 
     if answer:
       if len(branch.commits) > UNUSUAL_COMMIT_THRESHOLD: