simplify handling the thenable.

Removed the double try/catch

lib/rsvp/promise.js

@@ -131,16 +131,11 @@ function resolve(promise, value) {
 function handleThenable(promise, value) {
   var then = null;
 
-  if (objectOrFunction(value)) {
   try {
+    if (objectOrFunction(value)) {
       then = value.then;
-    } catch(e) {
-      reject(promise, e);
-      return true;
-    }
 
       if (isFunction(then)) {
-      try {
         then.call(value, function(val) {
           if (value !== val) {
             resolve(promise, val);
@@ -150,12 +145,14 @@ function handleThenable(promise, value) {
         }, function(val) {
           reject(promise, val);
         });
-      } catch (e) {
-        reject(promise, e);
-      }
+
         return true;
       }
     }
+  } catch (error) {
+    reject(promise, error);
+    return true;
+  }
 
   return false;
 }