Handle cases where openconnect folder is not within $PATH

[dktrkranz]

Forwarded from https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1084522

gp-saml-gui assumes openconnect is in $PATH. If that is not the case, it's not possible to execute the command.
Would it be possible and advisable to append at least /sbin folder to $PATH using os.environ, so to handle this scenario?
os.environ["PATH"] += os.pathsep + "/sbin"