Fix for reopened issue #2973, revert of a changeset rX on a target with merge history from same target does not work.
Fix for reopened issue #2973, revert of a changeset rX on a target with merge
history from same target does not work.

A reverse merge to a path from that path's own history may no-op in some
common mixed-rev WC situations, e.g. you make a change in rN then immediately
reverse merge rN.  If rN *didn't* affect the merge target, then the target's
working revision is still < N and the merge will no-op.  An update is needed
for the reverse merge to work, so give a warning suggesting this.

* subversion/libsvn_client/merge.c
 (calculate_remaining_ranges): Give a warning to the user that an update
 might be required to accomplish what they want.

Suggested by: cmpilato

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@869514 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion