these unused includes were identified by clang-include-cleaner. after
auditing these source files, all of the reports have been confirmed.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
We will add code that expects id to ip mapping to exist. If it does not
it is better to fail earlier during testing, so add a function that
calls internal error in case there is no mapping.