Description of problem:
The afaics only reliable way to get the kernel-devel package for the kernel variant (stock, PAE, debug, ...) you are running is a command like this:

 yum install "kernel-devel-uname-r = $(uname -r)"

But that does not work with dnf:

"""
[thl@thl-t420 ~]$ LC_ALL=C sudo dnf install "kernel-devel-uname-r = 3.12.8-300.fc20.x86_64"
No package kernel-devel-uname-r = 3.12.8-300.fc20.x86_64 available.
Error: Nothing to do.
[thl@thl-t420 ~]$ LC_ALL=C sudo yum install "kernel-devel-uname-r = 3.12.8-300.fc20.x86_64"
Loaded plugins: langpacks, refresh-packagekit
Resolving Dependencies
--> Running transaction check
---> Package kernel-devel.x86_64 0:3.12.8-300.fc20 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

======================================================================
 Package        Arch     Version              Repository         Size
======================================================================
Installing:
 kernel-devel   x86_64   3.12.8-300.fc20      updates-testing   8.5 M

Transaction Summary
======================================================================
Install  1 Package

Total download size: 8.5 M
Installed size: 32 M
Is this ok [y/d/N]: n
Exiting on user command
Your transaction was saved, rerun it with:
 yum load-transaction /tmp/yum_save_tx.2014-01-18.12-44.LtIaEC.yumtx
[thl@thl-t420 ~]$ 
"""

Version-Release number of selected component (if applicable):
dnf-0.4.11-1.fc20.noarch

Additional Info:
Quote from a earlier IRC-Discussion in #yum:
"""
(13:51:50) knurd: is it a known #dnf limitation that ' dnf install "kernel-devel-uname-r = 3.12.6-300.fc20.x86_64" ' doesn't work (in F20; yes, dnf can see that package), or is that worth reporting a bug?
(13:53:18) knurd: s/reopening/opening/ 
(14:01:59) akozumpl: knurd: that should work, open a bug and we will take a look
(16:05:43) geppetto: Pretty sure knurd's problem is that dnf doesn't parse "dnf update foo=bah"
(16:09:03) geppetto: Dito. install
"""