soup: use default proxy resolver instead of deprecated GNOME proxy resolver

Apparently there's no reason to use it any longer. Drop libsoup-gnome
dependency while at it, now that we don't need anything from it any
more (it only consists entirely of deprecated API now anyways).

https://bugzilla.gnome.org/show_bug.cgi?id=693911

configure.ac

@@ -824,14 +824,7 @@ AG_GST_CHECK_FEATURE(SHOUT2, [Shoutcast/Icecast client library], shout2, [
 dnl *** soup ***
 translit(dnm, m, l) AM_CONDITIONAL(USE_SOUP, true)
 AG_GST_CHECK_FEATURE(SOUP, [soup http client plugin (2.4)], souphttpsrc, [
-  PKG_CHECK_MODULES(SOUP, libsoup-gnome-2.4 >= 2.3.2, [
-    HAVE_SOUP="yes"
-    AC_DEFINE(HAVE_LIBSOUP_GNOME, 1, [soup gnome integration])
-  ],[
-    PKG_CHECK_MODULES(SOUP, libsoup-2.4 >= 2.26.1, HAVE_SOUP="yes", [
-      HAVE_SOUP="no"
-    ])
-  ])
+  PKG_CHECK_MODULES(SOUP, libsoup-2.4 >= 2.26.1, [HAVE_SOUP="yes"], [HAVE_SOUP="no"])
   AC_SUBST(SOUP_CFLAGS)
   AC_SUBST(SOUP_LIBS)
 ])

ext/soup/gstsouphttpsrc.c

@@ -77,11 +77,7 @@
 #endif
 #include <gst/gstelement.h>
 #include <gst/gst-i18n-plugin.h>
-#ifdef HAVE_LIBSOUP_GNOME
-#include <libsoup/soup-gnome.h>
-#else
 #include <libsoup/soup.h>
-#endif
 #include "gstsouphttpsrc.h"
 
 #include <gst/tag/tag.h>
@@ -1214,9 +1210,7 @@ gst_soup_http_src_start (GstBaseSrc * bsrc)
         soup_session_async_new_with_options (SOUP_SESSION_ASYNC_CONTEXT,
         src->context, SOUP_SESSION_USER_AGENT, src->user_agent,
         SOUP_SESSION_TIMEOUT, src->timeout,
-#ifdef HAVE_LIBSOUP_GNOME
-        SOUP_SESSION_ADD_FEATURE_BY_TYPE, SOUP_TYPE_PROXY_RESOLVER_GNOME,
-#endif
+        SOUP_SESSION_ADD_FEATURE_BY_TYPE, SOUP_TYPE_PROXY_RESOLVER_DEFAULT,
         NULL);
   } else {
     src->session =