This change renames the following 2 apis:
* mdadm_create -> md_create
* mdadm_detail -> md_detail

This is more consistent with list_md_devices, and removes a reference to an
implementation detail from the api.

This change involves rewriting make-fedora-img.sh in perl. This allows the
flexibility to write mdadm.conf containing whichever uuids where randomly
generated when the md devices were created.

./run can now be run in a separate build directory. Since some files
needed in the image checks are found in the source tree (but not the
build tree), the source tree location is passed to make-*-img.sh via
an environment variable.

This avoids conflicts with the globally installed libguestfs
appliance, or lets us build in multiple local directories at the same
time without conflicts.

This updates commit d95874db3dc6c415061b86275d03770b4f28ffbb.

Remove the hack that let you run ./fish/guestfish or
./fuse/guestmount.  You now have to do:

  ./run ./fish/guestfish
or
  ./run ./fuse/guestmount

to run these programs without installing.

It turns out that db_load incrementally updates the database (instead
of writing a new one).  Remove the old database to force db_load to
write a new one.

This also ensures that we handle write failure gracefully.