Client doesn't recover from DNS refreshes

[leonmaia]

Right now finagle-postgres caches the DNS resolution forever when retrieving custom types from Postgres. That causes to the client to be forever dead even if the naming resolution succedes afterward, causing to Finagle stop complaining about Name resolution failed but still causing failures when trying to query anything.

[info] 18:38:46.899 DEBUG [finagle/netty4-4] connection-1 - Sent frontend message of type: com.twitter.finagle.postgres.messages.Sync$
[info] 18:38:46.899 DEBUG [finagle/netty4-4] state machine-1 - Received event com.twitter.finagle.postgres.messages.Sync$ in state com.twitter.finagle.postgres.connection.Connected$
[info] 18:38:46.899 DEBUG [finagle/netty4-4] state machine-1 - Transitioning to state com.twitter.finagle.postgres.connection.Syncing$ and emiting result
[info] 18:38:46.900 DEBUG [finagle/netty3-2] connection-1 - Received backend message of type: com.twitter.finagle.postgres.messages.ReadyForQuery
[info] 18:38:46.900 DEBUG [finagle/netty3-2] state machine-1 - Received event com.twitter.finagle.postgres.messages.ReadyForQuery in state com.twitter.finagle.postgres.connection.Syncing$
[info] 18:38:46.900 DEBUG [finagle/netty3-2] state machine-1 - Transitioning to state com.twitter.finagle.postgres.connection.Connected$ and emiting result
[info] 18:38:46.900 DEBUG [finagle/netty3-2] connection-1 - Emitting result com.twitter.finagle.postgres.messages.ReadyForQueryResponse$
[info] 18:38:46.901 WARN  [finagle/netty3-2] c.t.o.s.m.NoBrokersAvailableExceptionMapper - Name resolution failed with No hosts are available for db, Dtab.base=[], Dtab.local=[]. Aborting.

For now as a workaround we can create the client adding withDefaultTypes() and that will make it work. But only if all the types needed by the application are described in: https://github.com/finagle/finagle-postgres/blob/master/src/main/scala/com/twitter/finagle/postgres/PostgresClient.scala#L84