The log message regex has been

[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]{3}\+[0-9]{4}: [0-9]+: debug|info|warning|error :

The precedence of '|' is high though, so this is equivalent to matching

   [0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]{3}\+[0-9]{4}: [0-9]+: debug

Or

   info

Or

   warning

Or

   error :

Which is clearly not what it should have done. This caused the code to
skip over things which are not log messages. The solution is to simply
add brackets.

A test case is also added to validate correctness.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 5787f0b9)