[bug-inetutils] Fix ping6 bug in tests

[jb999]

Without ping6 errno2 is currently the result of test -x $PING6, which makes the 
test fail erroneously.

diff -Nur inetutils-1.9.2.orig/tests/ping-localhost.sh 
inetutils-1.9.2/tests/ping-localhost.sh
--- inetutils-1.9.2.orig/tests/ping-localhost.sh        2013-09-26 
11:36:38.000000000 +0200
+++ inetutils-1.9.2/tests/ping-localhost.sh     2014-11-09 13:11:17.469541235 
+0100
@@ -54,7 +54,10 @@
 test $errno -eq 0 || echo "Failed at pinging $TARGET." >&2
 
 # Host might not have been built with IPv6 support..
-test -x $PING6 && $PING6 -n -c 1 $TARGET6 || errno2=$?
+if [ -x $PING6 ]; then
+  $PING6 -n -c 1 $TARGET6 || errno2=$?
+fi
+
 test $errno2 -eq 0 || echo "Failed at pinging $TARGET6." >&2
 
 test $errno -eq 0 || exit $errno