[source] Revert "sysupgrade: run only one instance at a time."

[LEDE Commits]

jow pushed a commit to source.git, branch master:
https://git.lede-project.org/361c8b4ee4a20035d4c967d9d67db90d53e924a2

commit 361c8b4ee4a20035d4c967d9d67db90d53e924a2
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Fri May 26 14:48:05 2017 +0200

    Revert "sysupgrade: run only one instance at a time."
    
    This reverts commit e96a9a9af82c00dcce606a84a7bb87a00411385d.
    
    The change breaks sysupgrade through LuCI and two-stage sysupgrade on
    NAND targets. There is also a mismatch of file paths in lock and unlock
    operations.
    
    This commit was apparently neither properly tested, nor reviewed, so
    drop it for now.
    
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 package/base-files/files/sbin/sysupgrade | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/package/base-files/files/sbin/sysupgrade b/package/base-files/files/sbin/sysupgrade
index 1eede14..c095ca8 100755
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -47,20 +47,6 @@ while [ -n "$1" ]; do
 	shift;
 done
 
-# just one instance
-if  ! lock -n /tmp/sysupgrade.lock
-then
-	echo "Another instance of sysupgrade already running"
-	echo "If you are sure this is wrong remove file /tmp/sysupgrade.lock"
-	exit 1
-fi
-
-# make sure the lock is removed when done even when killed
-finish() {
-	lock -u /var/sysupgrade.lock
-}
-trap finish EXIT INT TERM
-
 export CONFFILES=/tmp/sysupgrade.conffiles
 export CONF_TAR=/tmp/sysupgrade.tgz