ctags: Include new annotations to ctags ignore list.

ctags: Include new annotations to ctags ignore list.

The annotation OVS_NO_THREAD_SAFETY_ANALYSIS and OVS_LOCKABLE are
not part of the list, so ctags can't find functions using them.

The annotation list comes from a regex and to include more items
make the regex more difficult to read and maintain. Convert to a
static list because it isn't supposed to change much and there
is no standard names.

Also add a comment to remind to keep the list up-to-date.

Signed-off-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: William Tu <u9012063@gmail.com>