BUG/MINOR: quic: Possible infinite loop in quic_build_post_handshake_frames()

BUG/MINOR: quic: Possible infinite loop in quic_build_post_handshake_frames()

This loop is due to the fact that we do not select the next node before
the conditional "continue" statement. Furthermore the condition and the
"continue" statement may be removed after replacing eb64_first() call
by eb64_lookup_ge(): we are sure this condition may not be satisfied.
Add some comments: this function initializes connection IDs with sequence
number 1 upto <max> non included.
Take the opportunity of this patch to remove a "return" wich broke this
traces rule: for any function, do not call TRACE_ENTER() without TRACE_LEAVE()!
Add also TRACE_ERROR() for any encoutered errors.

Must be backported to 2.6