Add missing CoUninitialize.

For each CoInitialize we have to call CoUninitialize.
(cherry picked from commit ac1c62c8)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

modules/access/dshow/dshow.cpp

@@ -2021,6 +2021,7 @@ static int ConfigDevicesCallback( vlc_object_t *p_this, char const *psz_name,
     if( !p_item )
     {
         free( psz_device );
+        CoUninitialize();
         return VLC_SUCCESS;
     }
 
@@ -2039,7 +2040,11 @@ static int ConfigDevicesCallback( vlc_object_t *p_this, char const *psz_name,
 
         /* Enumerate devices */
         FindCaptureDevice( p_this, NULL, &list_devices, b_audio );
-        if( !list_devices.size() ) return VLC_EGENERIC;
+        if( !list_devices.size() )
+        {
+            CoUninitialize();
+            return VLC_EGENERIC;
+        }
         devicename = *list_devices.begin();
     }