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

contrib/dracut/90zfs/mount-zfs.sh.in

@@ -66,7 +66,7 @@ if import_pool "${ZFS_POOL}" ; then
 			ask_for_password \
 				--tries 5 \
 				--prompt "Encrypted ZFS password for ${ENCRYPTIONROOT}: " \
-				--cmd "zfs load-key ${ENCRYPTIONROOT}"
+				--cmd "zfs load-key '${ENCRYPTIONROOT}'"
 		fi
 	fi
 	# Let us tell the initrd to run on shutdown.