Retrieves security context of the keychain application.
Keychain application has a special management access to all stored identities and is able to perform deletion of all identities from storage.
The default implementation returns a context either set in Config, or if not set, a value specified through a configure --enable-keychain option (see <link linkend="gsignond-building">Building gsignond</link>), or if that is not set either then an empty string "" is returned.
If gSSO was compiled with --enable-debug and SSO_KEYCHAIN_SYSCTX environment variable is set, then the value of that variable is used to set the returned system context instead.
security context of the keychain application.