Quality the postmap command in postfix::hash

Fix #75 and #85

manifests/hash.pp

@@ -66,6 +66,7 @@ define postfix::hash (
 
   exec {"generate ${name}.db":
     command     => "postmap ${name}",
+    path        => $::path,
     #creates    => "${name}.db", # this prevents postmap from being run !
     subscribe   => File[$name],
     refreshonly => true,

spec/classes/postfix_mta_spec.rb

@@ -4,6 +4,7 @@ describe 'postfix::mta' do
   let (:facts) { {
     :lsbdistcodename => 'wheezy',
     :osfamily        => 'Debian',
+    :path            => '/foo/bar',
   } }
   let :pre_condition do
     "class { 'postfix':

spec/defines/postfix_hash_spec.rb

@@ -5,6 +5,7 @@ describe 'postfix::hash' do
   let (:facts) { {
     :lsbdistcodename => 'wheezy',
     :osfamily        => 'Debian',
+    :path            => '/foo/bar',
   } }
   let :pre_condition do
     "class { '::postfix': }"