BUG/MINOR: h3: fix BUG_ON() crash with glitch on htx_set_eom() failure

BUG/MINOR: h3: fix BUG_ON() crash with glitch on htx_set_eom() failure

In case of htx_set_eom() failure, qcc_set_error() is used both for DATA
and trailers parsing, setting INTERNAL_ERROR as value. Both parsers
return a negative value to interrupt h3_rcv_buf() parsing loop. However,
this causes a crash as qcc_set_error() is called a second time on the
function epilogue.

Fix this by removing qcc_set_error() usage in both h3_data_to_htx() /
h3_trailers_to_htx(). They still return a negative value, which is now
properly handled in h3_rcv_buf() epilogue : INTERNAL_ERROR is set as
both h3c <err> and h3s <err> are unset.

This must be backported up to 3.0.