MB-11066: Unit tests for config_parse

Add unit test for config_parse functionality. Initially this is to
test the current config parsing.

Change-Id: I8ce6f6311b403336c8f9a041e9ca540fe0919df7
Reviewed-on: http://review.couchbase.org/40750
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>