rdp: Support FreeRDP-1.2.0-beta1-android9

Fix build errors.

  CC       access/librdp_plugin_la-rdp.lo
access/rdp.c: In function ‘Open’:
access/rdp.c:431:5: error: implicit declaration of function ‘freerdp_channels_global_init’ [-Werror=implicit-function-declaration]
     freerdp_channels_global_init();
     ^
access/rdp.c: In function ‘Close’:
access/rdp.c:507:5: error: implicit declaration of function ‘freerdp_channels_global_uninit’ [-Werror=implicit-function-declaration]
     freerdp_channels_global_uninit();
     ^

freerdp channels global functions were removed from FreeRDP repository
in commit 2a82684521dc8b23ae92e284e866227e5194a7bb.

commit 2a82684521dc8b23ae92e284e866227e5194a7bb
Author: Marc-André Moreau <marcandre.moreau@gmail.com>
Date:   Wed Jun 11 16:27:31 2014 -0400

    channels: cleanup unused freerdp channels global functions
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 5c07f87a773153c128b3a771ed61e7915cd8fe18)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/access/rdp.c

@@ -428,7 +428,9 @@ static int Open( vlc_object_t *p_this )
     if ( p_sys->f_fps <= 0 ) p_sys->f_fps = 1.0;
     p_sys->i_frame_interval = 1000000 / p_sys->f_fps;
 
+#if FREERDP_VERSION_MAJOR == 1 && FREERDP_VERSION_MINOR < 2
     freerdp_channels_global_init();
+#endif
 
     p_sys->p_instance = freerdp_new();
     if ( !p_sys->p_instance )
@@ -504,7 +506,9 @@ static void Close( vlc_object_t *p_this )
 
     freerdp_disconnect( p_sys->p_instance );
     freerdp_free( p_sys->p_instance );
+#if FREERDP_VERSION_MAJOR == 1 && FREERDP_VERSION_MINOR < 2
     freerdp_channels_global_uninit();
+#endif
 
     if ( p_sys->p_block )
         block_Release( p_sys->p_block );