`_read_log()` calls `_log_streamline()` when it handles `socket.timeout`
exception. This change ensures `_log_streamline()` don't raise another
exception:
```
Traceback (most recent call last):'
File "/var/lib/zuul/ansible/2.9/zuul/ansible/callback/zuul_stream.py", line 137, in _read_log'
s = socket.create_connection((ip, port), 5)'
File "/usr/lib/python3.6/socket.py", line 724, in create_connection'
raise err'
File "/usr/lib/python3.6/socket.py", line 713, in create_connection'
sock.connect(sa)'
socket.timeout: timed out'
'
During handling of the above exception, another exception occurred:'
'
Traceback (most recent call last):'
File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner'
self.run()'
File "/usr/lib/python3.6/threading.py", line 864, in run'
self._target(*self._args, **self._kwargs)'
File "/var/lib/zuul/ansible/2.9/zuul/ansible/callback/zuul_stream.py", line 152, in _read_log'
% (ip, port))'
File "/var/lib/zuul/ansible/2.9/zuul/ansible/callback/zuul_stream.py", line 202, in _log_streamline'
ts, ln = line.split(' | ', 1)"
ValueError: not enough values to unpack (expected 2, got 1)'
```
Change-Id: Ifeea230d1285ab62acf11a0ed37e38e508e1dba8
2e79671991