fix(ci): fix email addresses at start of pipeline

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

ci-scripts/Jenkinsfile-GitLab-Docker

@@ -103,6 +103,8 @@ pipeline {
           echo "Git URL    is ${GIT_URL}"
 
           if ("MERGE".equals(env.gitlabActionType)) {
+            // Filling the committer email in case of error
+            gitCommitAuthorEmailAddr = env.gitlabUserEmail
             try {
               myShCmd('docker image inspect --format="Size = {{.Size}} bytes" vpp-upf-base:' + VPP_UPF_U18_BASE_IMAGE_TAG, rem_u18_host_flag, rem_u18_host_user, rem_u18_host)
             } catch (Exception e) {
@@ -119,8 +121,9 @@ pipeline {
                 error "Stopping pipeline!"
               }
             }
-            gitCommitAuthorEmailAddr = env.gitlabUserEmail
           } else {
+            // Filling the committer email in case of error
+            gitCommitAuthorEmailAddr = sh returnStdout: true, script: 'git log -n1 --pretty=format:%ae ${GIT_COMMIT}'
             gitCommitAuthorEmailAddr = gitCommitAuthorEmailAddr.trim()
           }
           if (params.DockerHubCredentials == null) {