jenkins: removed lock since there are concurent builds disabled

Jenkinsfile

@@ -17,8 +17,6 @@ pipeline {
     PACKAGE_NAME = 'nm-os'
     SLACK_TOKEN = '54fghFEpv1Rmf6GJ4gJ7cL2y'
 
-    LOCK_BUILD = "buildjob"
-
     MACHINE = "${MACHINE_TYPE}"
 
     SHARED_BUILD = "${WORKSPACE}/build"
@@ -65,16 +63,13 @@ pipeline {
     stage('clean') {
       when { expression { return params.CLEAN_BUILD } }
       steps {
-        lock("${env.LOCK_BUILD}") {
         dir ("${SHARED_BUILD}/tmp") { deleteDir() }
         dir ("${SHARED_BUILD}/tmp-glibc") { deleteDir() }
       }
     }
-    }
 
     stage('build') {
       steps {
-        lock("${env.LOCK_BUILD}") {
         script {
           build_and_archive()
         }
@@ -84,7 +79,6 @@ pipeline {
         sh "rm -rf ${WORKSPACE}/tmp"
       }
     }
-    }
   } // stages
 }