fix a separate race case

In a very close race, one side can first see the duplicate nvr
during the get_build check in new_build, which leads to an
attempt to recycle, which fails because the duplicate is in the
BUILDING state.

kojihub/kojihub.py

@@ -4861,8 +4861,9 @@ def get_next_build(build_info):
     for try_no in range(2, 10):
         savepoint = Savepoint('get_next_build_pre_insert')
         try:
-            return new_build(build_info)
-        except IntegrityError:
+            # using strict so we don't try to recycle
+            return new_build(build_info, strict=True)
+        except (IntegrityError, koji.GenericError):
             savepoint.rollback()
             build_info['release'] = get_next_release(build_info, try_no)
     # otherwise