[PATCH 3/5] site.c (we_have_priority): Fix unintended `&&'.

[Ian Jackson]

Mark Wooding writes ("[PATCH 3/5] site.c (we_have_priority): Fix unintended `&&'."):
> `CAPAB_PRIORITY_MOBILE' is 0x80000000, which is nonzero, so that doesn't
> change the outcome.  So the code is only checking whether the local and
> remote capabilities overlap at all, which seems unhelpful.
> 
> Instead, check that both advertise `CAPAB_PRIORITY_MOBILE' here.

Thanks.  We discussed the implications IRL.

The effect is that a new secnet would always think the peer had
advertised CAPAB_PRIORITY_MOBILE.  This might (with roughly 50%
probability) mess up resolution of crossed key setup attempts
involving a mobile end and mixed secnet versions.

The consequences would be mitigated by 19074a85692b
  site: Randomise key setup retry time
so the key setup would very likely eventually succeed.

I have added this information to the commit message.

Ian.