fix(server-side-image-map): return as needs review rather than failure

lib/checks/shared/exists.js

@@ -1 +1 @@
-return true;
+return undefined;

lib/checks/shared/exists.json

@@ -5,7 +5,7 @@
 		"impact": "minor",
 		"messages": {
 			"pass": "Element does not exist",
-			"fail": "Element exists"
+			"incomplete": "Element exists"
 		}
 	}
 }

test/checks/shared/exists.js

@@ -1,7 +1,7 @@
 describe('exists', function() {
 	'use strict';
 
-	it('should return true', function() {
-		assert.isTrue(checks.exists.evaluate());
+	it('should return undefined', function() {
+		assert.isUndefined(checks.exists.evaluate());
 	});
 });

test/integration/rules/server-side-image-map/server-side-image-map.html

@@ -1,2 +1,2 @@
-<p><img ismap src="image.jpg" id="fail" /></p>
+<p><img ismap src="image.jpg" id="incomplete" /></p>
 <p><img src="image.jpg" id="pass" /></p>

test/integration/rules/server-side-image-map/server-side-image-map.json

@@ -1,5 +1,5 @@
 {
 	"description": "server-side-image-map test",
 	"rule": "server-side-image-map",
-	"violations": [["#fail"]]
+	"incomplete": [["#incomplete"]]
 }