With these installed, currently running kernel-4.0.4-303:
dnf-1.0.0-1.fc22.noarch
yum-3.4.3-505.fc22.noarch
kernel-4.0.4-303.fc22.x86_64
kernel-core-4.0.3-300.fc22.x86_64
kernel-core-4.0.4-301.fc22.x86_64
kernel-core-4.0.4-303.fc22.x86_64
kernel-debug-devel-4.0.4-303.fc22.x86_64
kernel-headers-4.0.4-303.fc22.x86_64
kernel-modules-4.0.3-300.fc22.x86_64
kernel-modules-4.0.4-301.fc22.x86_64
kernel-modules-4.0.4-303.fc22.x86_64

[beland@localhost ~]$ sudo dnf install --allowerasing ./kernel-4.0.2-300.fc22.x86_64.rpm ./kernel-modules-4.0.2-300.fc22.x86_64.rpm ./kernel-core-4.0.2-300.fc22.x86_64.rpm 
Last metadata expiration check performed 2:24:36 ago on Wed Jun 10 10:55:20 2015.
Error: conflicting requests.
conflicting requests

[beland@localhost ~]$ sudo yum-deprecated install ./kernel-4.0.2-300.fc22.x86_64.rpm ./kernel-modules-4.0.2-300.fc22.x86_64.rpm ./kernel-core-4.0.2-300.fc22.x86_64.rpm 
Yum command has been deprecated, use dnf instead.
See 'man dnf' and 'man yum2dnf' for more information.

Examining ./kernel-4.0.2-300.fc22.x86_64.rpm: kernel-4.0.2-300.fc22.x86_64
Marking ./kernel-4.0.2-300.fc22.x86_64.rpm to be installed
Examining ./kernel-modules-4.0.2-300.fc22.x86_64.rpm: kernel-modules-4.0.2-300.fc22.x86_64
Marking ./kernel-modules-4.0.2-300.fc22.x86_64.rpm to be installed
Marking ./kernel-modules-4.0.2-300.fc22.x86_64.rpm to be installed
Marking ./kernel-modules-4.0.2-300.fc22.x86_64.rpm to be installed
Examining ./kernel-core-4.0.2-300.fc22.x86_64.rpm: kernel-core-4.0.2-300.fc22.x86_64
Marking ./kernel-core-4.0.2-300.fc22.x86_64.rpm to be installed
Marking ./kernel-core-4.0.2-300.fc22.x86_64.rpm to be installed
Marking ./kernel-core-4.0.2-300.fc22.x86_64.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package kernel.x86_64 0:4.0.2-300.fc22 will be installed
---> Package kernel-core.x86_64 0:4.0.2-300.fc22 will be installed
---> Package kernel-modules.x86_64 0:4.0.2-300.fc22 will be installed
--> Finished Dependency Resolution
--> Running transaction check
---> Package kernel-core.x86_64 0:4.0.3-300.fc22 will be erased
---> Package kernel-modules.x86_64 0:4.0.3-300.fc22 will be erased
--> Finished Dependency Resolution

Dependencies Resolved

============================================================================================================================================
 Package                      Arch                 Version                        Repository                                           Size
============================================================================================================================================
Installing:
 kernel                       x86_64               4.0.2-300.fc22                 /kernel-4.0.2-300.fc22.x86_64                       0.0  
 kernel-core                  x86_64               4.0.2-300.fc22                 /kernel-core-4.0.2-300.fc22.x86_64                   41 M
 kernel-modules               x86_64               4.0.2-300.fc22                 /kernel-modules-4.0.2-300.fc22.x86_64                17 M
Removing:
 kernel-core                  x86_64               4.0.3-300.fc22                 installed                                            41 M
 kernel-modules               x86_64               4.0.3-300.fc22                 installed                                            17 M

Transaction Summary
============================================================================================================================================
Install  3 Packages
Remove   2 Packages

and that works just fine.