interface: fix memory leak

Signed-off-by: Tristan Matthews <le.businessman@gmail.com>
(cherry picked from commit c53f31a51223a9d8c0c6e07b5d705d7a096dc963)

src/interface/interface.c

@@ -207,6 +207,7 @@ int libvlc_InternalAddIntf(libvlc_int_t *libvlc, const char *name)
                          "Use 'cvlc' to use vlc without interface."));
         }
         ret = intf_Create(playlist, intf);
+        free(intf);
         name = "default";
     }
     if (ret != VLC_SUCCESS)