.fixtures.yml: Fix augeas module name

I'm not sure if the dependency is even used, or there are no tests for
it.

.fixtures.yml

@@ -1,5 +1,3 @@
-# This file can be used to install module dependencies for unit testing
-# See https://github.com/puppetlabs/puppetlabs_spec_helper#using-fixtures for details
 ---
 fixtures:
   repositories:
@@ -10,5 +8,5 @@ fixtures:
     yumrepo_core: https://github.com/puppetlabs/puppetlabs-yumrepo_core
     chocolatey: https://github.com/puppetlabs/puppetlabs-chocolatey
     redis: https://github.com/voxpupuli/puppet-redis
-    augeas: https://github.com/puppetlabs/puppetlabs-augeas_core
+    augeas_core: https://github.com/puppetlabs/puppetlabs-augeas_core
     icinga2: https://github.com/voxpupuli/puppet-icinga2