Added os_command_line to property keys

Updated key listing for libvirt driver with os_command_line.

Change-Id: Ia34e3092a6c3209e05d174ea42cc4b35113baff2
Closes-bug: #1307272

doc/cli-reference/ch_cli_glance_property_keys.xml

@@ -222,6 +222,14 @@
                 <td><literal>vga</literal>, <literal>cirrus</literal>, <literal>vmvga</literal>,
                         <literal>xen</literal>, or <literal>qxl</literal></td>
             </tr>
+            <tr valign="top">
+                <td>libvirt API driver</td>
+                <td>os_command_line</td>
+                <td>The kernel command line to be used by the libvirt driver, instead of the
+                    default. For linux containers (LXC), the value is used as arguments for
+                    initialization.</td>
+                <td/>
+            </tr>
             <tr valign="top">
                 <td>VMware API driver</td>
                 <td>vmware_adaptertype</td>
@@ -268,4 +276,4 @@
             </tr>
         </tbody>
     </table>
-</chapter>
+</chapter>