ssh: fix bug in PermitRemoteOpen which caused it to ignore...

its first argument unless it was one of the special keywords "any" or
"none".

Obtained from: OpenSSH-portable commit b3daa8dc5823
Sponsored by: The FreeBSD Foundation

(cherry picked from commit 94e21add45344f0669f910ea77db499e8c892c90)
(cherry picked from commit 375bb3704d1371dec08f49cf8767f7b98162da34)