[...]

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.
If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:
  git checkout -b new_branch_name
HEAD is now at 159a758... - merged 12736 from PLD
error: HEAD does not point to a branch
fatal: @{u} - not something we can merge
Available branches: master
--2014-09-26 19:18:13--  http://df.tld-linux.org/distfiles/by-md5/5/4/54fef4e59386bac53e57822deffeef32/geninitrd-12736.tar.gz
Resolving df.tld-linux.org (df.tld-linux.org)... 46.4.78.55
Connecting to df.tld-linux.org (df.tld-linux.org)|46.4.78.55|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 119846 (117K) [application/x-gzip]
Saving to: 'geninitrd-12736.tar.gz'
     0K .......... .......... .......... .......... .......... 42% 1.78M 0s
    50K .......... .......... .......... .......... .......... 85% 3.85M 0s
   100K .......... .......                                    100% 10.9M=0.04s
2014-09-26 19:18:13 (2.75 MB/s) - 'geninitrd-12736.tar.gz' saved [119846/119846]
Building target platforms: i686-linux
Wrote: /home/users/builder/rpm/SRPMS/geninitrd-12736-1.src.rpm
exit status 0
Tagging with prefix: auto/ti/
HEAD is now at 159a758... - merged 12736 from PLD
error: HEAD does not point to a branch
fatal: @{u} - not something we can merge
Writing git revision for tag auto/ti/geninitrd-12736-1
On detached HEAD. Use -r BRANCHNAME to override
error: Macro %_builddir has empty body
error: Macro %_builddir has empty body
Executing(--clean):  env -i TMP=/home/users/builder/tmp PATH=/bin:/usr/bin:/usr/sbin:/sbin:/usr/X11R6/bin HOME=/home/users/builder TMPDIR=/home/users/builder/tmp  /bin/sh -e /home/users/builder/tmp/rpm-tmp.50792
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf geninitrd-12736
Begin-PLD-Builder-Info
Build-Time: user:2.49s sys:1.23s real:3.90s (faults io:0 non-io:181792)
Files queued for ftp:
    127078 geninitrd-12736-1.src.rpm
       187 geninitrd-12736-1.src.rpm.uploadinfo
End-PLD-Builder-Info