[Svnmerge] Patch for log message indentation

[Raman Gupta]

In Alan Barrett's message found here [1], he provided a patch for
indenting the log messages from the merge head.

[1] http://www.orcaware.com/pipermail/svnmerge/2006-February/000225.html

Personally, I also find the indented style much easier to read and would
like to see his patch committed. If there is some opposition to this,
then we can always add a --logindent=n option, where n defaults to 0.

Cheers,
Raman