Revert "Temporarily disable lint since it is failing builds."

This reverts commit dc3a323d635bc8f2a80ae3420a72fbc4ae8b98e1.

Change-Id: I6de1c9a246a6684e3990ac5bb0488dbbc75da1c3

src/main/groovy/android/support/SupportLibraryPlugin.groovy

@@ -68,7 +68,6 @@ class SupportLibraryPlugin implements Plugin<Project> {
             manifest.srcFile 'tests/AndroidManifest.xml'
         }
 
-        /*
         // Always lint check NewApi as fatal.
         library.lintOptions {
             abortOnError true
@@ -88,7 +87,6 @@ class SupportLibraryPlugin implements Plugin<Project> {
             // Always fail on NewApi.
             error 'NewApi'
         }
-        */
 
         // Library projects don't run lint by default, so set up dependency.
         project.tasks.release.dependsOn project.tasks.lint