Update rspec-puppet tests for 2.0

This patch replaces `subject` with `catalogue` for the raise_error
matchers because `subject` no longer contains Puppet errors. We also
unpin rspec-puppet.

Gemfile

@@ -3,7 +3,6 @@ source ENV['GEM_SOURCE'] || "https://rubygems.org"
 group :development, :unit_tests do
   gem 'rake',                    :require => false
   gem 'rspec-core', '3.1.7',     :require => false
-  gem 'rspec-puppet', '~> 1.0',  :require => false
   gem 'puppetlabs_spec_helper',  :require => false
   gem 'puppet-lint',             :require => false
   gem 'simplecov',               :require => false

spec/unit/defines/server/pg_hba_rule_spec.rb

@@ -110,7 +110,7 @@ describe 'postgresql::server::pg_hba_rule', :type => :define do
         }
       end
       it 'should fail parsing when type is not valid' do
-        expect {subject}.to raise_error(Puppet::Error,
+        expect { catalogue }.to raise_error(Puppet::Error,
           /The type you specified \[invalid\] must be one of/)
       end
     end
@@ -134,7 +134,7 @@ describe 'postgresql::server::pg_hba_rule', :type => :define do
       end
 
       it 'should fail parsing when auth_method is not valid' do
-        expect {subject}.to raise_error(Puppet::Error,
+        expect { catalogue }.to raise_error(Puppet::Error,
           /The auth_method you specified \[invalid\] must be one of/)
       end
     end
@@ -161,7 +161,7 @@ describe 'postgresql::server::pg_hba_rule', :type => :define do
       end
 
       it 'should fail parsing when auth_method is not valid' do
-        expect {subject}.to raise_error(Puppet::Error,
+        expect { catalogue }.to raise_error(Puppet::Error,
           /The auth_method you specified \[peer\] must be one of: trust, reject, md5, sha1, password, gss, sspi, krb5, ident, ldap, radius, cert, pam/)
       end
     end

spec/unit/defines/server/pg_ident_rule_spec.rb

@@ -59,7 +59,7 @@ describe 'postgresql::server::pg_ident_rule', :type => :define do
       }
     end
     it 'should fail because $manage_pg_ident_conf is false' do
-      expect {subject}.to raise_error(Puppet::Error,
+      expect { catalogue }.to raise_error(Puppet::Error,
                                       /postgresql::server::manage_pg_ident_conf has been disabled/)
     end
   end