Move zfs to top-level directory

With the merge of spl and zfs the extra level of directories is not needed
anymore.

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>

.gitmodules

@@ -1,3 +1,3 @@
 [submodule "zfs/upstream"]
-	path = zfs/upstream
+	path = upstream
 	url = ../mirror_zfs

Makefile

@@ -3,8 +3,8 @@ RELEASE=5.1
 # source form https://github.com/zfsonlinux/
 
 ZFSDIR=zfs-linux_${ZFSVER}
-ZFSSRC=zfs/upstream
-ZFSPKG=zfs/debian
+ZFSSRC=upstream
+ZFSPKG=debian
 
 ZFSVER != dpkg-parsechangelog -l ${ZFSPKG}/changelog -Sversion | cut -d- -f1