[source] scripts/feeds: use git rev-parse for getting revision

[LEDE Commits]

blogic pushed a commit to source.git, branch master:
https://git.lede-project.org/0a6439154a384d2782b2da80116a589b67a95f5a

commit 0a6439154a384d2782b2da80116a589b67a95f5a
Author: Rafał Miłecki <rafal at milecki.pl>
AuthorDate: Wed Nov 2 14:36:19 2016 +0100

    scripts/feeds: use git rev-parse for getting revision
    
    It provides simpler output so we don't need extra head and cut commands.
    
    Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
---
 scripts/feeds | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/scripts/feeds b/scripts/feeds
index 45239af..83007f5 100755
--- a/scripts/feeds
+++ b/scripts/feeds
@@ -130,19 +130,19 @@ my %update_method = (
 		'init_commit'   => "git clone '%s' '%s' && cd '%s' && git checkout -b '%s' '%s' && cd -",
 		'update'	=> "git pull --ff",
 		'controldir'	=> ".git",
-		'revision'	=> "git show --abbrev-commit HEAD | head -n 1 | cut -d ' ' -f 2 | tr -d '\n'"},
+		'revision'	=> "git rev-parse --short HEAD | tr -d '\n'"},
 	'src-git-full' => {
 		'init'          => "git clone '%s' '%s'",
 		'init_branch'   => "git clone --branch '%s' '%s' '%s'",
 		'init_commit'   => "git clone '%s' '%s' && cd '%s' && git checkout -b '%s' '%s' && cd -",
 		'update'	=> "git pull --ff",
 		'controldir'	=> ".git",
-		'revision'	=> "git show --abbrev-commit HEAD | head -n 1 | cut -d ' ' -f 2 | tr -d '\n'"},
+		'revision'	=> "git rev-parse --short HEAD | tr -d '\n'"},
 	'src-gitsvn' => {
 		'init'	=> "git svn clone -r HEAD '%s' '%s'",
 		'update'	=> "git svn rebase",
 		'controldir'	=> ".git",
-		'revision'	=> "git show --abbrev-commit HEAD | head -n 1 | cut -d ' ' -f 2 | tr -d '\n'"},
+		'revision'	=> "git rev-parse --short HEAD | tr -d '\n'"},
 	'src-bzr' => {
 		'init'		=> "bzr checkout --lightweight '%s' '%s'",
 		'update'	=> "bzr update",