Matt Mackall <mpm@selenic.com> [Tue, 07 Jun 2011 14:19:05 -0500] rev 14542
revert: drop requirement to use -r to revert with two parents
This reduces documentation confusion between the need to:
a) hg revert -a -r . (drop all changes from a merge)
b) hg up -C . (drop the second parent entirely)
Currently revert is one of two commands (the other being tag) that
still complains about uncommitted merges, dating from its former use
of a generic defaultrev function that aborted.