Enable prefix management when using ipaddress

Fix the case where we have RedHat, multiple ipaddress and multiple prefix.
The interface parameter `ipaddress` is the only option way to define multiple ips.

manifests/interface.pp

@@ -635,7 +635,10 @@ define network::interface (
     default => $peerntp,
   }
   case $ipaddr {
-    '': { $manage_ipaddr = $ipaddress}
+    '': {
+      $manage_ipaddr = $ipaddress
+      $manage_prefix = $prefix
+    }
     default: {
       if $ipaddr =~ /^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})\/([0-9]|[1-2][0-9]|3[0-2])$/ {
         $manage_ipaddr = $1

spec/defines/network_interface_spec.rb

@@ -102,6 +102,44 @@ describe 'network::interface' do
 
   end
 
+  context 'Test network:interface on RedHat 7 with multiple IPs, multiple prefix' do
+    let(:title) { 'eth0' }
+    let(:node) { 'rspec.example42.com' }
+    let(:facts) { { :architecture => 'x86_64', :osfamily => 'RedHat', :operatingsystem => 'RedHat', :operatingsystemmajrelease => '7' } }
+    let(:params) {
+      { 'enable'       =>  true,
+        'ipaddress'    =>  ['192.168.0.1','192.168.0.2'],
+        'prefix'       =>  ['24', '32']
+      }
+    }
+
+    it {
+      is_expected.to contain_file(NIC_CONFIG).with_ensure('present')
+    }
+
+    it {
+      is_expected.to contain_file(NIC_CONFIG).with_content(/IPADDR1=\"192.168.0.1\"/)
+    }
+
+    it {
+      is_expected.to contain_file(NIC_CONFIG).with_content(/IPADDR2=\"192.168.0.2\"/)
+    }
+
+    it {
+      is_expected.to contain_file(NIC_CONFIG).with_content(/ONBOOT=\"yes\"/)
+    }
+
+    it {
+      is_expected.to contain_file(NIC_CONFIG).with_content(/PREFIX1=\"24\"/)
+    }
+
+    it {
+      is_expected.to contain_file(NIC_CONFIG).with_content(/PREFIX2=\"32\"/)
+    }
+
+  end
+
+
   context 'Test network:interface on RedHat 8 with multiple IP rules' do
     let(:title) { 'eth0' }
     let(:node) { 'rspec.example42.com' }