another solution to undoing a bad merge

Hi Seth,

Ran into this problem today, and came up with another solution that worked well for us.
I wouldn't say it is a terribly clean one, but it is fairly simple.  I did try to discuss the
advantages and disadvantages of the two options fairly well.

These changes also correct the git command used to revert the merge,
which lacked the "-m 1" option needed to actually work.

There's also a real hyperlink to the howto/revert-a-faulty-merge.txt file.

@alex