GUAC-1292: Add "sftp-directory" parameter to VNC and RDP.

guacamole-ext/src/main/resources/org/glyptodon/guacamole/protocols/rdp.json

@@ -223,6 +223,10 @@
                 {
                     "name"  : "sftp-passphrase",
                     "type"  : "PASSWORD"
+                },
+                {
+                    "name"  : "sftp-directory",
+                    "type"  : "TEXT"
                 }
             ]
         }

guacamole-ext/src/main/resources/org/glyptodon/guacamole/protocols/vnc.json

@@ -97,6 +97,10 @@
                 {
                     "name"  : "sftp-passphrase",
                     "type"  : "PASSWORD"
+                },
+                {
+                    "name"  : "sftp-directory",
+                    "type"  : "TEXT"
                 }
             ]
         },