Update pip module to support Red Hat distros.

Adds a new pip::params module where we set parameters based on
the operating system.

Updates the pip::init module so that it makes use of distro specific
parameters.

Also, includes a change to pip::init so that a soft link is
created for /usr/bin/pip (pointing to /usr/bin/pip-python). This
is required in order for the Puppet pip provider to work on Red Hat
distributions. Seems like we should push a fix into Puppet for this
as well but having this live here for now seems reasonable.

Change-Id: Ifee6bc42fabcf65ee1241ffac38f3bead7335be1
Reviewed-on: https://review.openstack.org/18904
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins

modules/pip/manifests/init.pp

@@ -1,12 +1,24 @@
 # Class: pip
 #
 class pip {
-  package { 'python-all-dev':
+  include pip::params
+
+  package { $::pip::params::python_devel_package:
     ensure => present,
   }
 
-  package { 'python-pip':
+  package { $::pip::params::python_pip_package:
     ensure  => present,
-    require => Package['python-all-dev'],
+    require => Package[$::pip::params::python_devel_package]
   }
+
+  if ($::operatingsystem == 'Redhat' or $::operatingsystem == 'Fedora') {
+
+    file { '/usr/bin/pip':
+      ensure => 'link',
+      target => '/usr/bin/pip-python',
+    }
+
+  }
+
 }

modules/pip/manifests/params.pp

@@ -0,0 +1,19 @@
+# Class: pip::params
+#
+# This class holds parameters that need to be
+# accessed by other classes.
+class pip::params {
+  case $::osfamily {
+    'Fedora', 'Redhat': {
+      $python_devel_package = 'python-devel'
+      $python_pip_package   = 'python-pip'
+    }
+    'Debian', 'Ubuntu': {
+      $python_devel_package = 'python-all-dev'
+      $python_pip_package   = 'python-pip'
+    }
+    default: {
+      fail("Unsupported osfamily: ${::osfamily} The 'pip' module only supports osfamily Fedora, Redhat, Debian, or Ubuntu.")
+    }
+  }
+}