Use unittest2 for rhel6 compatibility

Fixes: https://pagure.io/koji/issue/830

tests/test_cli/data/image-build-config.conf

@@ -0,0 +1,30 @@
+[image-build]
+name = fedora-server-docker
+version = 26
+target = f26-candidate
+install_tree = https://alt.fedoraproject.org/pub/alt/releases/26/Cloud/$arch/os/
+arches = x86_64,ppc,arm64
+can_fail=ppc,arm64
+
+format = qcow2,rhevm-ova,vsphere-ova
+distro = Fedora-26
+repo = https://alt.fedoraproject.org/pub/alt/releases/26/Cloud/$arch/os/
+disk_size = 20
+
+ksversion = DEVEL
+kickstart = fedora-26-server-docker.ks
+ksurl = git://git.fedorahosted.org/git/spin-kickstarts.git?fedora26#68c40eb7
+specfile = git://git.fedorahosted.org/git/spin-kickstarts.git?spec_templates/fedora26#68c40eb7
+
+[ova-options]
+vsphere_product_version=26
+rhevm_description=Fedora Cloud 26
+vsphere_product_vendor_name=Fedora Project
+ovf_memory_mb=6144
+rhevm_default_display_type=1
+vsphere_product_name=Fedora Cloud 26
+ovf_cpu_count=4
+rhevm_os_descriptor=Fedora-26
+
+[factory-parameters]
+factory_test_ver=1.0