SERVER-12572 Informatively fail attempts to build C++ client driver targets

The MongoDB C++ client driver now resides in a separate repo and is maintained
independently of the server. The targets in this repo that used to build or test
the driver will now print an error message explaining the change and referring
users to the relevant documentation.
SERVER-12993: drop db in test until fixed
dropdb_race.js: switch to use fsync instead of j writeConcern
SERVER-12262 re-enable test for negation of in query
Merge remote-tracking branch 'upstream/master'