CLEANUP: mux-h1: rename all occurrences of stconn "cs" to "sc"

Function arguments and local variables called "cs" were renamed to
"sc" to avoid future confusion. There were also 2 places in traces
where "cs" used to display the stconn, which were turned to "sc".
h1s_upgrade_cs() and h1s_new_cs() were both renamed to _cs.
1 file changed