registry: use sqlite3_busy_timeout
registry: use sqlite3_busy_timeout

This caps CPU usage of MacPorts processes waiting for the registry
database while it is exclusively locked at about 1.5%. This could be
further reduced by using a busy handler and adjusting the timeout
depending on the number of calls to the busy handler.

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@100217 d073be05-634f-4543-b044-5fe20cf6d1d6

danchr/macports-base,macports/macports-base,macports/macports-base,danchr/macports-base,neverpanic/macports-base,neverpanic/macports-base