tests: fix warnings on tmdb full resolution
tests: fix warnings on tmdb full resolution

 warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
 guint count = grl_data_length (GRL_DATA (media), GRL_METADATA_KEY_REGION);
 ^~~~~

https://bugzilla.gnome.org/show_bug.cgi?id=768557

grilofw/grilo-plugins,jasuarez/grilo-plugins,jasuarez/grilo-plugins,GNOME/grilo-plugins,grilofw/grilo-plugins,GNOME/grilo-plugins