Description of problem:
katello-agent-3.1.0-2.el7sat.noarch (Satellite 6.3 tools) combined with gofer-2.7.7-2.el7sat.noarch (Satellite 6.2 tools) can cause issues when applying patches from Satellite.   

However, the katello-agent-3.1.0-2.el7sat.noarch RPM just has a dependency on gofer >= 2.7.6.  

Version-Release number of selected component (if applicable):
katello-agent-3.1.0-2.el7sat.noarch

How reproducible:
Consistently

Steps to Reproduce:
To show that katello-agent-3.1.0-2.el7sat.noarch (Satellite 6.3 tools) combined with gofer-2.7.7-2.el7sat.noarch (Satellite 6.2 tools) can cause issues:

*Built 2 VM's from RHEL 7.4 DVD ISO (TEST1, TEST2)

*Registered both with Satellite 6.3.1 (repositories: rhel-7-server-rpms, rhel-7-server-satellite-tools-6.3-rpms)

*Installed katello-agent-3.1.0-2.el7sat.noarch on both (which installed gofer-2.7.7-3.el7sat.noarch as dependency)

*Downgraded gofer on TEST2 only (rpm -Uvh --oldpackage gofer-2.7.7-2.el7sat.noarch.rpm; systemctl restart goferd)

*Ran "katello-package-upload" on both

*From Satellite: Hosts->Content Hosts->select TEST1, TEST2->Section Action->Manage Errata->Select All (179 packages)->Install Selected->via Katello Agent

*Wait for updates to complete on servers

*TEST1: yum history: 3 | System <unset>           | 2018-05-18 12:21 | I, O, U        |  195 EE

*TEST2: yum history: 3 | System <unset>           | 2018-05-18 12:21 | I, O, U        |  196 *<

*TEST2: yum history info 3:  shows Aborted, and warning: %postun(gofer-2.7.7-2.el7sat.noarch) scriptlet failed, signal 15

*TEST2: yum history: shows 184 duplicate packages (i.e. "sudo-1.8.19p2-13.el7.x86_64 is a duplicate with sudo-1.8.19p2-10.el7.x86_64")

*Reboot both TEST1 and TEST2

*TEST1 boots with no issues

*TEST2 boots to "kernel panic - not syncing VFS: Unable to mount root fs on unknown-block(0,0)


Actual results:
Server with katello-agent-3.1.0-2.el7sat.noarch (Satellite 6.3 tools) combined with gofer-2.7.7-2.el7sat.noarch (Satellite 6.2 tools) fails to boot after RHEL 7.4 to RHEL 7.5 upgrade.

Expected results:
If katello-agent-3.1.0-2.el7sat.noarch needs gofer-2.7.7-3.el7sat.noarch to work properly, it should have a dependency on that version.   

Additional info:
The Satellite 6.3 upgrade documentation (https://access.redhat.com/documentation/en-us/red_hat_satellite/6.3/pdf/upgrading_and_updating_red_hat_satellite/Red_Hat_Satellite-6.3-Upgrading_and_Updating_Red_Hat_Satellite-en-US.pdf) says to upgrade the Satellite agent by running: 

yum upgrade katello-agent katello-host-tools katello-host-toolsfact-plugin
pulp-rpm-handlers qpid-proton-c

None of these packages depend on gofer-2.7.7-3.el7sat.noarch, so it isn't updated.   This can create the situation above under "Steps to reproduce" were the katello-agent is updated, but gofer is not, and then the server is later patched from RHEL 7.4 to RHEL 7.5 which will result in the server not booting.