nfsd: initialize nfsd versions before creating svc

nfsd: initialize nfsd versions before creating svc

Commit 59db4a0c102e0de226a3395dbf25ea51bf845937 "nfsd: move more into
nfsd_startup()" inadvertently moved nfsd_versions after
nfsd_create_svc().  On older distributions using an rpc.nfsd that does
not explicitly set the list of nfsd versions, this results in
svc-create_pooled() being called with an empty versions array.  The
resulting incomplete initialization leads to a NULL dereference in
svc_process_common() the first time a client accesses the server.

Move nfsd_reset_versions() back before the svc_create_pooled(); this
time, put it closer to the svc_create_pooled() call, to make this
mistake more difficult in the future.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>