BUG/MINOR: server-state: properly handle the case where the base is not set

The refactoring in commit 131b07be3 ("MEDIUM: server: Refactor
apply_server_state() to make it more readable") made the global
server_state_base be dereferenced before being checked, resulting
in a crash on certain files.

This happened in 2.4-dev10, no backport is needed.
1 file changed