panoramix: obsolete bools are not deprecated aliases

An obsolete item is one that is not used anymore.
Aliases are used when the name of an item changes.

For some reason, this also fixes a memory leak.
Regression from [5768f298].

modules/video_filter/panoramix.c

@@ -165,9 +165,9 @@ vlc_module_begin()
     add_integer_with_range( CFG_PREFIX "bz-whitelevel-green", 0, 0, 255, NULL, GGAMMA_WL_TEXT, GGAMMA_WL_LONGTEXT, true )
     add_integer_with_range( CFG_PREFIX "bz-whitelevel-blue", 0, 0, 255, NULL, BGAMMA_WL_TEXT, BGAMMA_WL_LONGTEXT, true )
 #ifndef WIN32
-    add_deprecated_alias( CFG_PREFIX "xinerama" );
+    add_obsolete_bool( CFG_PREFIX "xinerama" );
 #endif
-    add_deprecated_alias( CFG_PREFIX "offset-x" )
+    add_obsolete_bool( CFG_PREFIX "offset-x" )
 #endif
 
     add_string( CFG_PREFIX "active", NULL, NULL, ACTIVE_TEXT, ACTIVE_LONGTEXT, true )