change error msg in setclientcert test case

Author: chronolaw

t/162-socket-tls-handshake.t

@@ -273,7 +273,7 @@ hello, [email protected],O=OpenResty,ST=California,C=US
 --- request
 GET /t
 --- response_body
-failed to setclientcert: bad client cert type
+failed to setclientcert: bad cert arg: cdata expected, got string
 --- no_error_log
 [alert]
 [error]
@@ -311,7 +311,7 @@ failed to setclientcert: bad client cert type
 --- request
 GET /t
 --- response_body
-failed to setclientcert: bad client pkey type
+failed to setclientcert: bad cert arg: cdata expected, got string
 --- no_error_log
 [alert]
 [error]