[RFC] Should "log --cc" imply "log --cc -p"?

I think a natural way to ask reviewing the recent merges while
showing tricky ones would be to say:

	$ git log --first-parent --cc master..pu

But this does not to show what I expect to see, which is an output
of:

	$ git log --first-parent --cc -p master..pu

This is only a minor irritation, but I think it might make sense to
make it notice the --cc in the former and turn -p on automatically.

The same for

	$ git log --cc next~3..next

which may make sense to turn into "git log -p --cc next~3..next".

When deciding if the above makes sense, there are a few things to
know to be true as prerequisites for the discussion:

 * Neither of these

	$ git log --first-parent -p master..pu
	$ git log -p master..pu

   shows any patches, and it is not a bug.  No patches are shown for
   merges unless -m is given, and when -m is given, we give pairwise
   2-way diffs for the number of parents.

 * We recently tweaked this:

	$ git log --first-parent -m -p master..pu

   to omit diffs with second and later parents, as that is what the
   user wishes with --first-parent.

 * The "--cc" option, when comparing two trees (i.e. showing a
   non-merge commit), is designed to show a normal patch.  In other
   words, you can view "--cc" as a modifier when you request a patch
   output format with "-p".  For "git show", "--cc -p" is turned on
   by default, and giving "-m" explicity (i.e. "git show -m") you
   can turn it off and have it do "-m -p" instead.