Check for revoked subkeys before checking the signature. BZ 1778784

The reverse order resulted in error "Invalid GPG Key from
<path to GPG key>: signature 9 doesn't bind subkey to key, type is
subkey revocation" when the package was signed with a GPG key
with revoked subkey.

yum/pgpmsg.py

@@ -1074,6 +1074,12 @@ def load(self, pkts) :
  pkt_idx = pkt_idx + 1
  is_revoked = 0
 
+ # there may optionally be a revocation
+ if pkt_idx < len(pkts) and pkts[pkt_idx].pkt_typ == CTB_PKT_SIG and pkts[pkt_idx].sig_type == SIG_TYPE_SUBKEY_REVOKE :
+ is_revoked = 1
+ subkey.append(pkts[pkt_idx])
+ pkt_idx = pkt_idx + 1
+
  # there must be one signature following the subkey that binds it to the main key
  if pkt_idx >= len(pkts) :
  raise ValueError('subkey at index %d was not followed by a signature' % (pkt_idx-1))
@@ -1083,12 +1089,6 @@ def load(self, pkts) :
 
  pkt_idx = pkt_idx + 1
 
- # there may optionally be a revocation
- if pkt_idx < len(pkts) and pkts[pkt_idx].pkt_typ == CTB_PKT_SIG and pkts[pkt_idx].sig_type == SIG_TYPE_SUBKEY_REVOKE :
- is_revoked = 1
- subkey.append(pkts[pkt_idx])
- pkt_idx = pkt_idx + 1
-
  # append the user ID and signature(s) onto the list
  if is_revoked :
  self.rvkd_subkeys.append(subkey)