[release] enable stage temporarily for bypassing input parameter (elastic#2265)

Author: v1v

.ci/release/Jenkinsfile

@@ -112,6 +112,9 @@ pipeline {
           }
         }
         stage('Set release version') {
+          when {
+            expression { return false }
+          }
           steps {
             dir("${BASE_DIR}"){
               script {
@@ -140,6 +143,24 @@ pipeline {
             }
           }
         }
+        stage('Set release version manually') {
+          steps {
+            dir("${BASE_DIR}"){
+              script {
+                def user_release_version = input(message: "Please enter version to release:", parameters: [[
+                    $class: 'StringParameterDefinition',
+                    name: 'Release version',
+                    defaultValue: "",
+                    description: "Input release version without '-SNAPSHOT' suffix"
+                  ]])
+
+                env.RELEASE_TAG = "v" + user_release_version
+                env.RELEASE_VERSION = user_release_version
+                env.BRANCH_DOT_X = user_release_version.substring(0, user_release_version.indexOf('.'))+'.x'
+              }
+            }
+          }
+        }
         stage('Wait on internal CI') {
           when {
             expression { return false }