zdtm: use full paths in commands and log messages

I like copy past. Currently zdtm.sh uses paths relative to the
directory test, but I work ralative to the root of the source tree.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -431,8 +431,8 @@ EOF
 	for i in `seq $ITERATIONS`; do
 		local dump_only=
 		local postdump=
-		ddump=dump/$tname/$PID/$i
-		DUMP_PATH=`pwd`/$ddump
+		ddump=`readlink -fm dump/$tname/$PID/$i`
+		DUMP_PATH=$ddump
 		echo Dump $PID
 		mkdir -p $ddump