Make use of the new garbage-collection routines when closing a file.

svn path=/trunk/; revision=47550

epan/wmem/wmem_scopes.c

@@ -126,6 +126,10 @@ wmem_leave_file_scope(void)
 
     wmem_free_all(file_scope);
     in_file_scope = FALSE;
+
+    /* this seems like a good time to do garbage collection */
+    wmem_gc(file_scope);
+    wmem_gc(packet_scope);
 }
 
 /* Epan Scope */