Description of problem:
Steps to reproduce:
0. have hawkey 0.6.3-2.fc24 on your system (updated)
1. install yumex-dnf and dnfdaemon from copr timlau/yumex-dnf or fedora 24 repositories
2. start yumex-dnf
3. if yumex-dnf doesn't refresh package metadata, trigger it from sandwich menu

What happens:
dnfdaemon crashes with a segfault

What should happen:
No segfault

This regression was introduced in hawkey 0.6.3-2.fc24 and has not been present in 0.6.2-4.fc24. Also have a look at https://github.com/timlau/dnf-daemon/issues/3 .

Version-Release number of selected component:
dnfdaemon-0.3.14-1.fc24

Additional info:
reporter:       libreport-2.7.0
backtrace_rating: 4
cmdline:        /usr/bin/python3 /usr/share/dnfdaemon/dnfdaemon-system
crash_function: load_yum_repo
executable:     /usr/bin/python3.5
kernel:         4.5.2-302.fc24.x86_64
pkg_fingerprint: 3D03 BDC6 DD82 F6A5
pkg_vendor:     Fedora Project COPR (timlau/yumex-dnf)
reproducible:   The problem occurs regularly
runlevel:       N 5
type:           CCpp

Truncated backtrace:
Thread no. 1 (10 frames)
 #4 load_yum_repo at /usr/src/debug/hawkey-0.6.3/src/sack.c:568
 #5 hy_sack_load_repo at /usr/src/debug/hawkey-0.6.3/src/sack.c:999
 #6 load_repo at /usr/src/debug/hawkey-0.6.3/src/python/sack-py.c:455
 #7 PyCFunction_Call at /usr/src/debug/Python-3.5.1/Objects/methodobject.c:98
 #8 PyEval_EvalFrameEx at /usr/src/debug/Python-3.5.1/Python/ceval.c:4913
 #14 _PyEval_EvalCodeWithName at /usr/src/debug/Python-3.5.1/Python/ceval.c:3995
 #15 PyEval_EvalFrameEx at /usr/src/debug/Python-3.5.1/Python/ceval.c:4793
 #24 _PyEval_EvalCodeWithName at /usr/src/debug/Python-3.5.1/Python/ceval.c:3995
 #25 PyEval_EvalCodeEx at /usr/src/debug/Python-3.5.1/Python/ceval.c:4016
 #26 function_call at /usr/src/debug/Python-3.5.1/Objects/funcobject.c:632