do not include timestamp for syslog record

Including timestamp prevent syslog daemon from aggregating them.

with timestamps:
[WARN 2014-12-18 11:35:00] Received unexpected signal 13, ignoring [src/relay.c:659] sig_handler()
[WARN 2014-12-18 11:35:00] Received unexpected signal 13, ignoring [src/relay.c:659] sig_handler()
....
[WARN 2014-12-18 11:40:59] Received unexpected signal 13, ignoring [src/relay.c:659] sig_handler()

witout timestamps:
[WARN] Received unexpected signal 13, ignoring [src/relay.c:659] sig_handler()
last message repeated N times
block SIGPIPE signal

Logging inside SIGPIPE handler effectively creates infinite loop:
a) imagine that STDERR and/or syslog socket is closed for some reason
b) relay calls WARN or SAY
c) writting to STDERR or syslog triggers delivery of SIGPIPE
d) sighandler does WARN("Received unexpected signal %d, ignoring", signum);
e) goto c
add pid when dump to stderr
block all signals indside threads

let's receive all signals we're interested in main thread only