fix(tooltip): respect animate attribute

Previously, it was only possible to set animation to false with an empty
string and options.

Closes angular-ui#1418

Author: chrisirhc

src/tooltip/test/tooltip.spec.js

@@ -45,6 +45,10 @@ describe('tooltip', function() {
     expect( elmScope.tt_isOpen ).toBe( false );
   }));
 
+  it('should not animate on animation set to false', inject(function() {
+    expect( elmScope.tt_animation ).toBe( false );
+  }));
+
   it('should have default placement of "top"', inject(function() {
     elm.trigger( 'mouseenter' );
     expect( elmScope.tt_placement ).toBe( "top" );

src/tooltip/tooltip.js

@@ -261,10 +261,6 @@ angular.module( 'ui.bootstrap.tooltip', [ 'ui.bootstrap.position', 'ui.bootstrap
             scope.tt_placement = angular.isDefined( val ) ? val : options.placement;
           });
 
-          attrs.$observe(prefix + 'Animation', function (val) {
-            scope.tt_animation = angular.isDefined(val) ? !!val : options.animation;
-          });
-
           attrs.$observe( prefix+'PopupDelay', function ( val ) {
             var delay = parseInt( val, 10 );
             scope.tt_popupDelay = ! isNaN(delay) ? delay : options.popupDelay;
@@ -292,6 +288,9 @@ angular.module( 'ui.bootstrap.tooltip', [ 'ui.bootstrap.position', 'ui.bootstrap
             hasRegisteredTriggers = true;
           });
 
+          var animation = scope.$eval(attrs[prefix + 'Animation']);
+          scope.tt_animation = angular.isDefined(animation) ? !!animation : options.animation;
+
           attrs.$observe( prefix+'AppendToBody', function ( val ) {
             appendToBody = angular.isDefined( val ) ? $parse( val )( scope ) : appendToBody;
           });