FLUME-2497. Support fractional seconds in Syslog timestamps

This fixes a bug in the SyslogTcpSource and SyslogUdpSource where
fractional timestamps fail to parse.

(Johny Rufus via Mike Percy)
FLUME-2385. Remove incorrect log message at INFO level in Spool Directory Source.

(Phil Scala via Hari Shreedharan)
Merge remote-tracking branch 'remotes/origin/trunk' into trunk