GUACAMOLE-269: Add fields for controlling Backspace behavior.

guacamole-ext/src/main/resources/org/apache/guacamole/protocols/ssh.json

@@ -73,6 +73,11 @@
                 {
                     "name"  : "server-alive-interval",
                     "type"  : "NUMERIC"
+                },
+                {
+                    "name"    : "backspace",
+                    "type"    : "ENUM",
+                    "options" : [ "", "127", "8" ]
                 }
             ]
         },

guacamole-ext/src/main/resources/org/apache/guacamole/protocols/telnet.json

@@ -59,6 +59,17 @@
             ]
         },
 
+        {
+            "name" : "session",
+            "fields" : [
+                {
+                    "name"    : "backspace",
+                    "type"    : "ENUM",
+                    "options" : [ "", "127", "8" ]
+                }
+            ]
+        },
+
         {
             "name" : "typescript",
             "fields" : [