libtracker-extract: Made more resilient to dbus/splice failures
libtracker-extract: Made more resilient to dbus/splice failures

Now if one of both operations fail, the other is cancelled right
away, instead of having the petition wait forever for the other
part to be finished, which might never happen.

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