weston-log: rename a confusing parameter name in weston_compositor_add_log_scope()

In the function weston_compositor_add_log_scope() we have
a struct weston_log_context parameter that in the .c file
is named log_ctx. In the .h, the same parameter is named
compositor. This is confusing, since its type is not
struct weston_compositor, but struct weston_log_context.

Rename the parameter in the .h to log_ctx.

Signed-off-by: Leandro Ribeiro <leandrohr@riseup.net>

include/libweston/weston-log.h

@@ -63,7 +63,7 @@ typedef void (*weston_log_scope_cb)(struct weston_log_subscription *sub,
 				    void *user_data);
 
 struct weston_log_scope *
-weston_compositor_add_log_scope(struct weston_log_context *compositor,
+weston_compositor_add_log_scope(struct weston_log_context *log_ctx,
 				  const char *name,
 				  const char *description,
 				  weston_log_scope_cb new_subscription,