rtpulpfecenc: fix unmatched `g_slice_free()`
commit 009bdcae
ulpfecenc: slightly safer dispose impl
Technically dispose can be called more than once (even if gstelement is
not actually set up to do that) so need to protect against that.
commit e14e00b8
ulpfecenc: fix unmatched free() call
One must always match a g_slice_new with a g_slice_free and a g_new with
a g_free. This was not the case for the internal ctx struct.
commit a8bce316
rtpulpfecenc: add some debug logging
Like, what configuration we are using or whether a fec packet is
generated.