Fix zfsonlinux#81 - further snapshots were aborted after the pre-snapshot command failed once

Author: mateusz-kolecki

src/zfs-auto-snapshot.sh

@@ -197,7 +197,7 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 		then
 			if [ "$opt_pre_snapshot" != "" ]
 			then
-				do_run "$opt_pre_snapshot $ii $NAME" || RUNSNAP=0
+				do_run "$opt_pre_snapshot $ii $NAME" && RUNSNAP=1 || RUNSNAP=0
 			fi
 			if [ $RUNSNAP -eq 1 ] && do_run "zfs snapshot $PROPS $FLAGS '$ii@$NAME'"
 			then