Remove zerodisk from mcp offline image build

We don't need to extend image file and truncate it later
(it consumes extra 40 GB of jenkins slave for nothing)

Also add 'df -h' command to pipeline for better debugging

Closes-bug: PROD-35231
Change-Id: I7cea0f2bdd75c4a669e07e27a226d9da790a90fb
diff --git a/packer-image-buid.groovy b/packer-image-buid.groovy
index 2e90877..5a5bdd2 100644
--- a/packer-image-buid.groovy
+++ b/packer-image-buid.groovy
@@ -223,6 +223,8 @@
 
                             common.infoMsg("Run build with:")
                             sh(script: 'printenv|sort')
+                            common.infoMsg("Free disk space by 'df -h' command:")
+                            sh(script: 'df -h')
                             sh(script: "set -xe; packer build -only='openstack' ${_packer_args} -parallel=false template.json")
                             _os_private = "${workspace}/${job_env.BUILD_OS}/os_${job_env.BUILD_OS}.pem"
                             if (fileExists(_os_private)) {
@@ -255,6 +257,8 @@
                                  "PACKER_IMAGES_CACHE=${ImagesCacheFolder}"] + extra_vars_list) {
                             common.infoMsg("Run build with:")
                             sh(script: 'printenv|sort')
+                            common.infoMsg("Free disk space by 'df -h' command:")
+                            sh(script: 'df -h')
                             sh(script: "set -xe ; packer build -on-error=ask -only='qemu' ${_packer_args} -parallel=false template.json".toString())
 
                             def packerStatus = sh(script: "grep \"Some builds didn't complete successfully and had errors\" ${PACKER_LOG_PATH}", returnStatus: true)