Sorry for the delay.
I tried below change in kernel.spec and now with this patch, the build and source symlinks are moved into kernel-devel package.

This was been tested for Fedora 21 kernel-3.19.7-200
Source RPM : kernel-3.19.7-200.fc21.src.rpm

I request kernel package maintainers to please have look into it.

--- a/kernel-orig.spec    2015-05-08 03:06:43.000000000 +0530
+++ b/kernel.spec    2015-05-22 23:17:07.636035055 +0530
@@ -2252,8 +2252,6 @@ fi
 %dir /lib/modules\
 %dir /lib/modules/%{KVERREL}%{?2:+%{2}}\
 %dir /lib/modules/%{KVERREL}%{?2:+%{2}}/kernel\
 %ifarch %{vdso_arches}\
@@ -2263,6 +2261,8 @@ fi
 %{expand:%%files -f kernel-%{?2:%{2}-}modules.list %{?2:%{2}-}modules}\
 %{expand:%%files %{?2:%{2}-}devel}\
 %{expand:%%files %{?2:%{2}-}modules-extra}\

Thanks and Regards,
Deepu K S

On Tue, Apr 28, 2015 at 7:17 PM, Jonathan Underwood <jonathan.underwood@gmail.com> wrote:
On 28 April 2015 at 09:17, John Dodson <johnd@physiol.usyd.edu.au> wrote:
> Sorry - I've been offline for a bit.
> Thanks Deepu & others.
> I think the dangling symlink problem is now in the right place & will probably
> get some attention by at least being brought up & thought about.
> I'm sure the Kernel people will deal with it when they can & they will be moved
> to the -devel package appropriately.

I think there'll only be more progress on the issue if someone
proposes a packaging guideline draft along the lines of what Dominik
proposed earlier in the thread.