repo: capitalize default prompt char

It is common in command line tools to indicate what the default answer
will be if the user simply hits enter.  In repo, the display is just
"y/n" with no indication as to which is the default.  So change the n
to N in the messages since that is how repo operates.

Change-Id: I81819ae630355072eb0365e59168b0921289498f
diff --git a/subcmds/upload.py b/subcmds/upload.py
index a08926c..c152e75 100644
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@@ -73,7 +73,7 @@
 
 review.URL.autoupload:
 
-To disable the "Upload ... (y/n)?" prompt, you can set a per-project
+To disable the "Upload ... (y/N)?" prompt, you can set a per-project
 or global Git configuration option.  If review.URL.autoupload is set
 to "true" then repo will assume you always answer "y" at the prompt,
 and will not prompt you further.  If it is set to "false" then repo
@@ -171,7 +171,7 @@
       for commit in list:
         print '         %s' % commit
 
-      sys.stdout.write('to %s (y/n)? ' % remote.review)
+      sys.stdout.write('to %s (y/N)? ' % remote.review)
       answer = sys.stdin.readline().strip()
       answer = answer in ('y', 'Y', 'yes', '1', 'true', 't')
 
@@ -299,7 +299,7 @@
 
             # if they want to auto upload, let's not ask because it could be automated
             if answer is None:
-                sys.stdout.write('Uncommitted changes in ' + branch.project.name + ' (did you forget to amend?). Continue uploading? (y/n) ')
+                sys.stdout.write('Uncommitted changes in ' + branch.project.name + ' (did you forget to amend?). Continue uploading? (y/N) ')
                 a = sys.stdin.readline().strip().lower()
                 if a not in ('y', 'yes', 't', 'true', 'on'):
                     print >>sys.stderr, "skipping upload"