[libdmapsharing] dmap-share: Use idiomatic way of checking for errors

[W. Michael Petullo <wmpetullo src gnome org>]

commit f92c96974083faafd9475130b37cbb85bb61f376
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Jun 26 15:00:00 2017 +0200

    dmap-share: Use idiomatic way of checking for errors
    
    Use the retval of the API, instead of assuming that the API will always
    set the error (it'd be a bug, but at least we'd go down the correct
    branch).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766723
    
    Signed-off-by: W. Michael Petullo <mike flyn org>

 libdmapsharing/dmap-share.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/libdmapsharing/dmap-share.c b/libdmapsharing/dmap-share.c
index e92449f..a302e73 100644
--- a/libdmapsharing/dmap-share.c
+++ b/libdmapsharing/dmap-share.c
@@ -233,6 +233,7 @@ _dmap_share_server_start (DMAPShare *share)
        GError *error = NULL;
        GSList *listening_uri_list;
        SoupURI *listening_uri;
+       gboolean ret;
 
        share->priv->server = soup_server_new (NULL, NULL);
 
@@ -284,19 +285,19 @@ _dmap_share_server_start (DMAPShare *share)
                                 (SoupServerCallback) ctrl_int_adapter,
                                 share, NULL);
 
-       soup_server_listen_all (share->priv->server, desired_port, 0, &error);
+       ret = soup_server_listen_all (share->priv->server, desired_port, 0, &error);
 
-       if (error != NULL) {
+       if (ret == FALSE) {
                g_warning ("Unable to start music sharing server on port %d: %s. "
                           "Trying any open IPv6 port", desired_port, error->message);
                g_clear_error (&error);
 
-               soup_server_listen_all (share->priv->server, SOUP_ADDRESS_ANY_PORT,
-                                       0, &error);
+               ret = soup_server_listen_all (share->priv->server, SOUP_ADDRESS_ANY_PORT,
+                                             0, &error);
        }
 
        listening_uri_list = soup_server_get_uris (share->priv->server);
-       if (listening_uri_list == NULL) {
+       if (ret == FALSE || listening_uri_list == NULL) {
                g_warning ("Unable to start music sharing server on any port.");
                return FALSE;
        }