Fix two bugs in backup_functions.sh
Bug 1 (stop_p4broker timeout message): In stop_p4broker(), the timeout
error message referenced $maxStartDelay, which is undefined in that
function. The correct local variable is $maxStopDelay (declared at the
top of stop_p4broker()). With set -u active in the script, hitting this
code path would crash the script with an unbound variable error instead
of printing the intended timeout message. The equivalent code in
stop_p4d() and stop_p4p() correctly uses $maxStopDelay.
Bug 2 (typo in check_vars error message): The error message on line 75
read 'Aborting to to errors' (doubled word). Corrected to 'Aborting due
to errors'.