NFS: Move nfs4_get_session() into nfs4_session.h

This puts session related functions together in the same space.  I only
keep one version of this function, since this variable will always be
NULL when using NFS v4.0.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index d12ff93..b752d85 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -12,6 +12,7 @@
 #include "nfs42.h"
 #include "iostat.h"
 #include "pnfs.h"
+#include "nfs4session.h"
 #include "internal.h"
 
 #define NFSDBG_FACILITY NFSDBG_PROC