wvtest: fix build breakage

	* test compared 2 binary multiline strings that happened to have
		'!' at start which fooled wrapper into thinking test failed.
	* change compare to prepend <<< and >>> to output

Change-Id: Iab15354203509c71e84066b07b4537d54b0db555
diff --git a/cmds/wvtest/wvtest.sh b/cmds/wvtest/wvtest.sh
index 47b4366..19e0167 100644
--- a/cmds/wvtest/wvtest.sh
+++ b/cmds/wvtest/wvtest.sh
@@ -97,9 +97,9 @@
 	_wvfind_caller
 	_wvcheck $(_wvgetrv [ "$#" -eq 2 ]) "exactly 2 arguments"
 	echo "Comparing:" >&2
-	echo "$1" >&2
+	echo "$1" | sed -e 's/^/<<< /' >&2
 	echo "--" >&2
-	echo "$2" >&2
+	echo "$2" | sed -e 's/^/>>> /' >&2
 	_wvcheck $(_wvgetrv [ "$1" = "$2" ]) "'$1' = '$2'"
 }
 
@@ -109,9 +109,9 @@
 	_wvfind_caller
 	_wvcheck $(_wvgetrv [ "$#" -eq 2 ]) "exactly 2 arguments"
 	echo "Comparing:" >&2
-	echo "$1" >&2
+	echo "$1" | sed -e 's/^/<<< /' >&2
 	echo "--" >&2
-	echo "$2" >&2
+	echo "$2" | sed -e 's/^/>>> /' >&2
 	_wvcheck $(_wvgetrv [ "$1" != "$2" ]) "'$1' != '$2'"
 }