Bump ames protocol version. Now set in a single constant.

sys/vane/ames.hoon

@@ -4,6 +4,7 @@
   =>  =~
 ::  structures
 =,  ames
+=+  protocol-version=0
 |%
 +=  move  [p=duct q=(wind note:able gift:able)]         ::  local move
 --
@@ -385,7 +386,7 @@
             vix=(bex +((cut 0 [25 2] mag)))             ::  width of sender
             tay=(cut 0 [27 5] mag)                      ::  message type
         ==
-    ?>  =(7 vez)
+    ?>  =(protocol-version vez)
     ?>  =(chk (end 0 20 (mug bod)))
     :+  [(end 3 wix bod) (cut 3 [wix vix] bod)]
       (kins tay)
@@ -405,7 +406,7 @@
     =+  tay=(ksin q.kec)
     %+  mix
       %+  can  0
-      :~  [3 7]
+      :~  [3 protocol-version]
           [20 (mug bod)]
           [2 yax]
           [2 qax]
@@ -995,7 +996,7 @@
     ++  gnaw                                            ::    gnaw:am
       |=  [kay=cape ryn=lane pac=rock]                  ::  process packet
       ^-  [p=(list boon) q=fort]
-      ?.  =(7 (end 0 3 pac))  [~ fox]
+      ?.  =(protocol-version (end 0 3 pac))  [~ fox]
       =+  kec=(bite pac)
       ?:  (goop p.p.kec)  [~ fox]
       ?.  (~(has by urb.ton.fox) q.p.kec)