examples: fix warnings on example-tmdb
examples: fix warnings on example-tmdb

All -Wdeclaration-after-statement such as:

 warning: ISO C90 forbids mixed declarations and code
 const gchar *title = grl_media_get_title (media);
 ^~~~~

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

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