Remove the unused systemd requires.

rhpkg complains about this line now, so get rid of it

Related: rhbz#1059447
Check for preupgrade-assistant risks

If redhat-upgrade-tool is being used for a major version upgrade,
require that preupgrade-assistant has been run and has not detected any
medium, high or extreme risks to the upgrade. --force will disable this
check.

(cherry picked from commit 93677e7ef3b076559e6193e298f36f87139a60fc)

Resolves: rhbz#1059447
Don't display package problems covered by preupgrade-assistant

(cherry picked from commit a4a105f4c4e1a9b7d54563789161d375eac9af96)

Related: rhbz#1059447
Revise the preupgrade HIGH risk message.

Modify the high risk check to ask the user to continue. Include the
risks in the output. Use the return value of preupg to determine whether
riskcheck data is available to avoid having to know the path of the
xccdf file.

(cherry picked from commit 19bc6bd3f52e1f5676954b8c04c2775dec02d663)

Related: rhbz#1059447
Merge branch 'old-riskcheck' into old (#1059447)

This merges in changes for integration with preupgrade-assistant.
New version 0.7.8