sip-pipeline: Only use gstreamer debugging if option is set

Fixes build issues when gstreamer has not been compiled with debugging
enabled.

Fixes: #533

plugins/provider/sip/calls-sip-media-pipeline.c

@@ -24,6 +24,8 @@
 
 #define G_LOG_DOMAIN "CallsSipMediaPipeline"
 
+#include "calls-config.h"
+
 #include "calls-media-pipeline-enums.h"
 #include "calls-sip-media-pipeline.h"
 #include "calls-srtp-utils.h"
@@ -1140,6 +1142,7 @@ static void
 dump_pipeline_graph_to_path (GstBin     *bin,
                              const char *full_path)
 {
+  #ifdef CALLS_GST_DEBUG
   g_autoptr (GFile) file = NULL;
   char *dot_data;
 
@@ -1157,6 +1160,7 @@ dump_pipeline_graph_to_path (GstBin     *bin,
                        NULL,
                        on_dump_file_created,
                        dot_data);
+  #endif
 }