meta-flow: fix a typo in "MPLS Bottom of Stack Field" paragraph.

In the ovs-fields.7 manual page, the "MPLS Bottom of Stack Field" paragraph
says:
 * When mpls_bos is 1, there is another MPLS label following this one,
   so the Ethertype passed to pop_mpls should be an MPLS Ethertype. [...]

 * When mpls_bos is 0, this MPLS label is the last one, so the Ethertype
   passed to pop_mpls should be a non-MPLS Ethertype such as IPv4. [...]

The values 0 and 1 have been swapped: when BOS is 1,
then no more label stack entries follows.

Fixes: 96fee5e ("ovs-fields: New manpage to document Open vSwitch and OpenFlow fields.")
Reported-at: https://bugzilla.redhat.com/1842032
Reported-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Timothy Redaelli <tredaelli@redhat.com>
Acked-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

lib/meta-flow.xml

@@ -3920,18 +3920,18 @@ r r c c c.
 
       <ul>
         <li>
-          When <ref field="mpls_bos"/> is 1, there is another MPLS label
+          When <ref field="mpls_bos"/> is 0, there is another MPLS label
           following this one, so the Ethertype passed to <code>pop_mpls</code>
           should be an MPLS Ethertype.  For example: <code>table=0,
-          dl_type=0x8847, mpls_bos=1, actions=pop_mpls:0x8847,
+          dl_type=0x8847, mpls_bos=0, actions=pop_mpls:0x8847,
           goto_table:1</code>
         </li>
 
         <li>
-          When <ref field="mpls_bos"/> is 0, this MPLS label is the last one,
+          When <ref field="mpls_bos"/> is 1, this MPLS label is the last one,
           so the Ethertype passed to <code>pop_mpls</code> should be a non-MPLS
           Ethertype such as IPv4.  For example: <code>table=1, dl_type=0x8847,
-          mpls_bos=0, actions=pop_mpls:0x0800, goto_table:2</code>
+          mpls_bos=1, actions=pop_mpls:0x0800, goto_table:2</code>
         </li>
       </ul>
     </field>