dlm: move plock code from gfs2

Move the code that handles cluster posix locks from gfs2 into the dlm
so that it can be used by both gfs2 and ocfs2.

Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/Makefile b/fs/dlm/Makefile
index d248e60..ca1c912 100644
--- a/fs/dlm/Makefile
+++ b/fs/dlm/Makefile
@@ -10,6 +10,7 @@
 				midcomms.o \
 				netlink.o \
 				lowcomms.o \
+				plock.o \
 				rcom.o \
 				recover.o \
 				recoverd.o \