BUG/MINOR: h3: fix BUG_ON() crash on control stream alloc failure

BUG/MINOR: h3: fix BUG_ON() crash on control stream alloc failure

BUG_ON() from qcc_set_error() is triggered on HTTP/3 control stream
allocation failure. This is caused because both h3_finalize() and
qcc_init_stream_local() call qcc_set_error() which is forbidden to
prevent error code erasure.

Fix this by removing qcc_set_error() invocation from h3_finalize() on
allocation failure. Note that this function is still responsible to use
it on SETTING frame emission failure.

This was detected using -dMfail.

This must be backported up to 3.0.