remove compressed cache

The compression of the cache during initial build time and
the removal and (re)decompression of the cache for subsequent
builds takes a large amount of time and causes significant I/O.

This commit removes the compressed cache and, instead, keeps
the cache uncompressed and maintained in a known state.  If
the "applied-patch" file does not exist, then the cache is
in the unpatched state.  If the file does exist, the cache is
in a patched state and can be returned to an unpatched state
with "patch -R -p1 < applied-patch".

The if cache is detected and is in the patched state, the patch
is removed and vmlinux is rebuilt to obtain the base vmlinux.

Signed-off-by: Seth Jennings <sjenning@redhat.com>