Support modprobe style names in kpatch load

When the argument is a .ko file, it should be considered a path (i.e.
don't even look for it in the installed DB). When the argument is a
module name, it should be considered a loaded or installed module (and
then in the case of kpatch load we have to do a reverse translation of
all installed modules to see if any of them match).

Fixes #371 

Signed-off-by: Seth Jennings <sjenning@redhat.com>
I humbly accept your challenge to find more bugs. :p  This subtly changes the behavior of `kpatch load`: now the install dir takes priority over the local dir.  I think the original behavior was more intuitive.