Ensure drafts redisplay when refreshing the page

New draft comments did not redisplay when toggling between full
file and not full file mode, as new drafts were not available in
the cached script.  Invalidate the cached script when the drafts
are adjusted, ensuring we pick up the new one the next time through.

Change-Id: I1f2c2405c1fbae91a34d0c44c3aa6dacf8ad73bc
Signed-off-by: Shawn O. Pearce <sop@google.com>
3 files changed