fix mountpoint test to not prevemt mkfs_xxx from making image in any file

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

testsuite/runtest

@@ -1,20 +1,8 @@
 #!/bin/sh
-
 # Usage:
 # runtest [applet1] [applet2...]
 
-# Helper for helpers. Oh my...
-test x"$ECHO" != x"" || {
-	ECHO="echo"
-	test x"`echo -ne`" = x"" || {
-		# Compile and use a replacement 'echo' which understands -e -n
-		ECHO="$PWD/echo-ne"
-		test -x "$ECHO" || {
-			gcc -Os -o "$ECHO" ../scripts/echo.c || exit 1
-		}
-	}
-	export ECHO
-}
+. testing.sh
 
 # Run one old-style test.
 # Tests are stored in applet/testcase shell scripts.