Remove useless check for config-host.mak

If config-host.mak dont' exist, we have exited in the check at
the beginning of the file.
Once here, move the bits to the else part of the test at the beginning of
the file.

Patchworks-ID: 35191
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
