general: Remove a few unhelpful references to ‘master’

Some of these have a negative master/slave connotation, and they add no
value. Change or drop them.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

gio/gnetworkaddress.c

@@ -1108,7 +1108,7 @@ g_network_address_address_enumerator_next (GSocketAddressEnumerator  *enumerator
 
 /*
  * Each enumeration lazily initializes the internal address list from the
- * master list. It does this since addresses come in asynchronously and
+ * main list. It does this since addresses come in asynchronously and
  * they need to be resorted into the list already in use.
  */
 static GSocketAddress *

gio/tests/gapplication.c

@@ -140,7 +140,7 @@ basic (void)
 
   main_loop = g_main_loop_new (NULL, 0);
 
-  /* spawn the master */
+  /* spawn the main instance */
   spawn ("activated\n"
          "open file:///a file:///b\n"
          "exit status: 0\n", NULL,
@@ -191,7 +191,7 @@ test_remote_command_line (void)
                          NULL);
   g_object_unref (file);
 
-  /* spawn the master */
+  /* spawn the main instance */
   spawn (replies, NULL,
          "./cmd", NULL);
 
@@ -255,7 +255,7 @@ test_remote_actions (void)
 
   main_loop = g_main_loop_new (NULL, 0);
 
-  /* spawn the master */
+  /* spawn the main instance */
   spawn ("got ./cmd 0\n"
          "activate action1\n"
          "change action2 1\n"

gio/tests/socket-client.c

@@ -431,7 +431,7 @@ main (int argc,
     {
       if (!g_socket_close (socket, &error))
 	{
-	  g_printerr ("Error closing master socket: %s\n",
+	  g_printerr ("Error closing socket: %s\n",
 		      error->message);
 	  return 1;
 	}

gio/tests/socket-server.c

@@ -356,7 +356,7 @@ main (int argc,
 
   if (!g_socket_close (socket, &error))
     {
-      g_printerr ("Error closing master socket: %s\n",
+      g_printerr ("Error closing socket: %s\n",
 		  error->message);
       return 1;
     }