Fully rewrite existing change and do not amend

Currently if change exists on review, updateReleaseMetadata
method will download existing change and will do commit amend.

This leads to incremental changes - if some files were existing
in previous patchset and there are no such files in new commit,
resulting patchset will contain them anyway. To avoid this
we should disable amending on git commit.

Change-Id: I69611148b4116bcb3cd3b430033b137ecae9128b
Related-Prod: https://mirantis.jira.com/browse/PROD-32122
diff --git a/src/com/mirantis/mk/ReleaseWorkflow.groovy b/src/com/mirantis/mk/ReleaseWorkflow.groovy
index 7fbf065..fd39ea9 100644
--- a/src/com/mirantis/mk/ReleaseWorkflow.groovy
+++ b/src/com/mirantis/mk/ReleaseWorkflow.groovy
@@ -132,8 +132,6 @@
             changeNum = jsonChange['number']
             ChangeId = 'Change-Id: '
             ChangeId += jsonChange['id']
-            //get existent change from gerrit
-            gerrit.getGerritChangeByNum(gitCredentialsId, venvDir, repoDir, gitRemote, changeNum)
         } else {
             ChangeId = ''
             git.createGitBranch(repoDir, crTopic)
@@ -146,11 +144,7 @@
                |${ChangeId}
             """.stripMargin()
         //commit change
-        if (gerritChange) {
-            git.commitGitChanges(repoDir, commitMessage, changeAuthorEmail, changeAuthorName, false, true)
-        } else {
-            git.commitGitChanges(repoDir, commitMessage, changeAuthorEmail, changeAuthorName, false)
-        }
+        git.commitGitChanges(repoDir, commitMessage, changeAuthorEmail, changeAuthorName, false)
         //post change
         gerrit.postGerritReview(gitCredentialsId, venvDir, repoDir, changeAuthorName, changeAuthorEmail, gitRemote, crTopic, metadataGerritBranch)
     }