libweston: rename weston_output_destroy() to weston_output_release()

'release' is a more appropriate name because the function does not free
the underlying memory. The main reason for this is that we need the name
weston_output_destroy() for new API that actually will free also the
underlying memory.

Since the function is only used in backends and external backends are
not a thing, this does not cause libweston major version bump, even
though it does change the ABI. There is no way external users could have
successfully used this function.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Ian Ray <ian.ray@ge.com>
Acked-by Daniel Stone <daniels@collabora.com>
diff --git a/libweston/compositor.c b/libweston/compositor.c
index e647d30..53bbf55 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -4750,7 +4750,7 @@
  * Also notifies the compositor that an output is pending for
  * configuration.
  *
- * The opposite of this operation is built into weston_output_destroy().
+ * The opposite of this operation is built into weston_output_release().
  *
  * \memberof weston_output
  * \internal
@@ -4931,7 +4931,7 @@
  * \internal
  */
 WL_EXPORT void
-weston_output_destroy(struct weston_output *output)
+weston_output_release(struct weston_output *output)
 {
 	output->destroying = 1;