[...]

do so (now or later) by using -b with the checkout command again. Example:
  git checkout -b new_branch_name
HEAD is now at 602ccea... - updated to 1.5.1 (fixes CVE-2015-1802 CVE-2015-1803 CVE-2015-1804)
fatal: HEAD does not point to a branch
Available branches: master
--2015-05-08 07:00:49--  http://distfiles.pld-linux.org/distfiles/by-md5/9/6/96f76ba94b4c909230bac1e2dcd551c4/libXfont-1.5.1.tar.bz2
Resolving distfiles.pld-linux.org (distfiles.pld-linux.org)... 193.239.45.41
Connecting to distfiles.pld-linux.org (distfiles.pld-linux.org)|193.239.45.41|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 502903 (491K) [application/x-bzip2]
Saving to: 'libXfont-1.5.1.tar.bz2'
     0K .......... .......... .......... .......... .......... 10%  152K 3s
    50K .......... .......... .......... .......... .......... 20%  128K 3s
   100K .......... .......... .......... .......... .......... 30%  151K 2s
   150K .......... .......... .......... .......... .......... 40%  151K 2s
   200K .......... .......... .......... .......... .......... 50%  128K 2s
   250K .......... .......... .......... .......... .......... 61%  139K 1s
   300K .......... .......... .......... .......... .......... 71%  166K 1s
   350K .......... .......... .......... .......... .......... 81%  128K 1s
   400K .......... .......... .......... .......... .......... 91%  139K 0s
   450K .......... .......... .......... .......... .         100% 82.5K=3.7s
2015-05-08 07:00:53 (133 KB/s) - 'libXfont-1.5.1.tar.bz2' saved [502903/502903]
warning: Could not canonicalize hostname: giant
Building target platforms: i686-linux
Wrote: /home/users/builder/rpm/SRPMS/xorg-lib-libXfont-1.5.1-1.src.rpm
exit status 0
Tagging with prefix: auto/ti/
HEAD is now at 602ccea... - updated to 1.5.1 (fixes CVE-2015-1802 CVE-2015-1803 CVE-2015-1804)
fatal: HEAD does not point to a branch
Writing git revision for tag auto/ti/xorg-lib-libXfont-1.5.1-1
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 HOME=/home/users/builder PATH=/bin:/usr/bin:/usr/sbin:/sbin:/usr/X11R6/bin TMPDIR=/home/users/builder/tmp  /bin/sh -e /home/users/builder/tmp/rpm-tmp.18126
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf libXfont-1.5.1
Begin-PLD-Builder-Info
Build-Time: user:2.75s sys:1.33s real:18.95s (faults io:0 non-io:190124)
Files queued for ftp:
    510097 xorg-lib-libXfont-1.5.1-1.src.rpm
       195 xorg-lib-libXfont-1.5.1-1.src.rpm.uploadinfo
End-PLD-Builder-Info