SERVER-7231 Use ternary operator in LOG() macro and add necessary comparison operators
SERVER-7231 Use LOG(level) macro instead of log(level) function

Conflicts:
	src/mongo/client/distlock.cpp
	src/mongo/db/geo/haystack.cpp
	src/mongo/db/pdfile.cpp
	src/mongo/db/queryoptimizer.cpp
	src/mongo/db/repl/rs.cpp
	src/mongo/s/config.cpp
SERVER-7231 Removed log(level) functions
SERVER-7231 Construct log helper variables only when they will be logged
SERVER-7231 Fixed cases where LOG(level) macro is used with booleans

Conflicts:
	src/mongo/s/strategy_shard.cpp
Return nullstream in don't-log case of MONGO_LOG
SERVER-8244 Pass log levels from MONGO_LOG to Logstream

This is a partial reversion and change of commit
4db60cf23b58a7a5e177e69c142ab9e1503a3b1b.
Use fast thread-local for logging

Conflicts:
	src/mongo/util/log.cpp
Handle some missing log -> LOG conversions due to backports