tracker-extract-gstreamer: Fix nfo:channels and nfo:sampleRate
tracker-extract-gstreamer: Fix nfo:channels and nfo:sampleRate

tagreadbin provides these two values as ints, not uints.

Fixes part of NB#132761.

outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker