Add quotations for ${ENCRYPTIONROOT}

Add quotations for ${ENCRYPTIONROOT} to avoid breaking systems
with a space in the name.

Reviewed-by: bunder2015 <omfgbunder@gmail.com>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kash Pande <kash@tripleback.net>
Related-to: #8093
Closes #8114