nfsd: make expkey cache allocated per network namespace context

This patch also changes svcauth_unix_purge() function: added network namespace
as a parameter and thus loop over all networks was replaced by only one call
for ip map cache purge.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h
index 2e2af10..2c54683 100644
--- a/include/linux/sunrpc/svcauth.h
+++ b/include/linux/sunrpc/svcauth.h
@@ -130,7 +130,7 @@
 extern struct auth_domain *auth_domain_find(char *name);
 extern struct auth_domain *auth_unix_lookup(struct net *net, struct in6_addr *addr);
 extern int auth_unix_forget_old(struct auth_domain *dom);
-extern void svcauth_unix_purge(void);
+extern void svcauth_unix_purge(struct net *net);
 extern void svcauth_unix_info_release(struct svc_xprt *xpt);
 extern int svcauth_unix_set_client(struct svc_rqst *rqstp);