removing noise from grilo

[Víctor M. Jáquez L. <vjaquez igalia com>]

As discussed in b.g.o. 627864, there are a lot of trace messages along grilo
and grilo-plugins.

IMO those traces are just noise and they should be removed. Meanwhile Damien
suggest create another logging level for trace messages.

IMO tracing is not needed. If you want to trace, you probably need profiling,
and for that there are tools for it.

Any way, what should be do? a) remove trace messages; b) add the trace log
level

vmjl