messages: don't print timestamp in interactive mode

Internal messages submitted via the msg_XXXX API are printed on stderr
in a number of cases. When syslog-ng itself is doing that, a timestamp
is very useful, however when interactive tools do that (for example pdbtool)
the timestamp is not really needed.

So disable timestamps in interactive mode.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
dbparser: return a GError instance in all error cases

Some of the error cases when parsing the patterndb file were only logged,
but the return value didn't indicate an error, thus the parsing was
not terminated. This patch adds a GError return in these cases.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
pdbtool test: examples lacking $PROGRAM or $MESSAGE value are printed too

Previously examples that lack $PROGRAM or $MESSAGE value were not printed
to the test log at all. With this patch, the fact that these are ignored
is printed to stdout.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Merge branch '3.6/h/pdbtool-fixes'