Revert "Remove `-s sh` of check_access command"

This reverts commit 19a852ad2e633b2c6486984ee45f6f8d40f3e738.

The -s "sh" option to su command on Linux systems is necessary
because if the login shell of a user specified to the su command
is /bin/false or /usr/sbin/nologin etc, the tests will always fail.
make sh command passed to su command be a full path

to be more secure.
added -s /bin/sh option to su and runuser command to spec files
Merge pull request #226 from sohgo/revert_fix_pull_168

Revert and fix pull #168