Update angular-protractor.d.ts

Change string to the correct type, webdriver.promise.Promise.

angular-protractor/angular-protractor.d.ts

@@ -772,7 +772,7 @@ declare module protractor {
         /**
          * Returns the current absolute url from AngularJS.
          */
-        getLocationAbsUrl(): string;
+        getLocationAbsUrl(): webdriver.promise.Promise;
 
         /**
          * Pauses the test and injects some helper functions into the browser, so that
@@ -865,4 +865,4 @@ declare var element: protractor.Element;
 
 declare module 'protractor' {
     export = protractor;
-}
+}