ALBS-1030: Generate Devel section in packages.json

- Skip verifying an RPM signature if sigkeys are empty

pungi/phases/pkgset/pkgsets.py

@@ -889,6 +889,8 @@ class KojiMockPackageSet(KojiPackageSet):
             sigkey.lower() for sigkey in self.sigkey_ordering
             if sigkey is not None
         ]
+        if not sigkeys:
+            return True
         with open(rpm_path, 'rb') as fd:
             header = ts.hdrFromFdno(fd)
             signature = header[rpm.RPMTAG_SIGGPG] or header[rpm.RPMTAG_SIGPGP]