Update default branch for scratch and jats builds

Not using devel anymore; master will suffice.

dotfiles/config/mkittool/debstuff.ini

     scrap_storage = true
 
 [debstuff.def.group.jats]
-    branch = devel
+    branch = master
     uri_pattern = ~/vcs.jats/%s
 
 [debstuff.def.group.vpriv]
     storage_root = ~/pals/vornet-private/deb
 
 [debstuff.def.group.vscratch]
-    branch = devel
+    branch = master
     uri_pattern = ~/vcs.mystream/%s