adopt a more stable proxy configuration

adopt proxy configuration as documented by @niq (Nick Kew)

   http://www.apachetutor.org/admin/reverseproxies documents the

This pattern is more resilient to shaky redirects from the backend
This commit fixes #300.

spec/defines/vhost_spec.rb

@@ -208,8 +208,10 @@
           :attr     => 'proxy_dest',
           :value    => 'http://fake.com',
           :match    => [
-            '  ProxyPass        / http://fake.com/',
-            '  ProxyPassReverse / http://fake.com/',
+            '  ProxyPass          / http://fake.com/',
+            '  <Location          />',
+            '    ProxyPassReverse /',
+            '  </Location>',
           ],
           :notmatch => /ProxyPass .+!$/,
         },
@@ -231,10 +233,14 @@
             { 'path' => '/path-b', 'url' => 'http://fake.com/b/' },
           ],
           :match    => [
-            '  ProxyPass        /path-a http://fake.com/a/',
-            '  ProxyPassReverse /path-a http://fake.com/a/',
-            '  ProxyPass        /path-b http://fake.com/b/',
-            '  ProxyPassReverse /path-b http://fake.com/b/',
+            '  ProxyPass          /path-a http://fake.com/a/',
+            '  <Location          /path-a/>',
+            '    ProxyPassReverse /',
+            '  </Location>',
+            '  ProxyPass          /path-b http://fake.com/b/',
+            '  <Location          /path-b/>',
+            '    ProxyPassReverse /',
+            '  </Location>',
           ],
           :notmatch => /ProxyPass .+!$/,
         },

templates/vhost/_proxy.erb

@@ -8,14 +8,17 @@
   </Proxy>
 <%- end -%>
 <% [@proxy_pass].flatten.compact.each do |proxy| %>
-  ProxyPass        <%= proxy['path'] %> <%= proxy['url'] %>
-  ProxyPassReverse <%= proxy['path'] %> <%= proxy['url'] %>
+  ProxyPass <%= proxy['path'] %> <%= proxy['url'] %>
+  <Location <%= proxy['path']%>/>
+    ProxyPassReverse /
+  </Location>
 <% end %>
 <% if @proxy_dest -%>
 <% Array(@no_proxy_uris).each do |uri| %>
   ProxyPass        <%= uri %> !
 <% end %>
-  ProxyPass        / <%= @proxy_dest %>/
-  ProxyPassReverse / <%= @proxy_dest %>/
-  ProxyPreserveHost On
+  ProxyPass          / <%= @proxy_dest %>/
+  <Location          />
+    ProxyPassReverse /
+  </Location>
 <% end -%>