travis: Disable soup in "all" test

On Ubuntu 12.04, there seems to be a resource leak related to pthread keys
when initializing glib or related libraries more than once. With our repeated
initialization for libstrongswan tests, we hit the following error:

  Lib (gthread-posix.c): Unexpected error from C library during
  'pthread_key_create': Resource temporarily unavailable.

The problem is not reproducible on a newer Gnome stack, hence we disable the
glib based soup plugin until we have a more recent Ubuntu on Travis.

scripts/test.sh

@@ -34,7 +34,7 @@ all)
 			--disable-dumm --disable-kernel-pfroute --disable-keychain
 			--disable-lock-profiler --disable-maemo --disable-padlock
 			--disable-osx-attr --disable-tkm --disable-uci --disable-aikgen
-			--disable-systemd
+			--disable-systemd --disable-soup
 			--disable-svc --disable-dbghelp-backtraces --disable-socket-win
 			--disable-kernel-wfp --disable-kernel-iph --disable-winhttp"
 	if test "$LEAK_DETECTIVE" = "yes"; then