Update tests for rspec-puppet 2 and future parser

This patch changes the raise_error matchers to use `catalogue` instead
of `subject` since `subject` is not evaluated the way it used to be;
changes a parameter value from empty string to nil to be compatible
with the future parser, and unpins 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/classes/mysql_server_spec.rb

@@ -110,7 +110,7 @@ describe 'mysql::server' do
               :max_queries_per_hour     => nil,
               :max_updates_per_hour     => nil,
               :max_user_connections     => nil,
-              :password_hash            => ''
+              :password_hash            => nil
             )}
           end
 

spec/defines/mysql_db_spec.rb

@@ -16,7 +16,7 @@ describe 'mysql::db', :type => :define do
 
         it 'should report an error when ensure is not present or absent' do
           params.merge!({'ensure' => 'invalid_val'})
-          expect { subject }.to raise_error(Puppet::Error,
+          expect { catalogue }.to raise_error(Puppet::Error,
                                             /invalid_val is not supported for ensure\. Allowed values are 'present' and 'absent'\./)
         end
 
@@ -47,7 +47,7 @@ describe 'mysql::db', :type => :define do
 
         it 'should report an error if sql isn\'t a string or an array' do
           params.merge!({'sql' => {'foo' => 'test_sql', 'bar' => 'test_2_sql'}})
-          expect { subject }.to raise_error(Puppet::Error,
+          expect { catalogue }.to raise_error(Puppet::Error,
                                             /\$sql must be either a string or an array\./)
         end