Checking WITH_OPENSSL flag might not be correct

[ajindal1]

In this PR (#1262), for Python 3.11 there was a new flag added, WITH_OPENSSL. Later it is being checked whether the value of WITH_OPENSSL is empty or not. However, since the variable is only set for Python 3.11 case, it doesn't exist for other cases and the code fails because set -u is used (treat unset variables as error). I think this can be solved by either of two options:

1. Checking if the variable is set or not, which can be done by the below command as detailed in this link (https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash).
   if [[ -z ${WITH_OPENSSL+x} ]]; then

2. Setting WITH_OPENSSL="" in case it is not set in the else statement while setting it for Python 3.11.

[ptrblck]

I'm seeing the same issues in #1271 and was already starting to debug and agree with the description.

CC @atalman

[malfet]

Fixed by #1276