Revert build plan.

Jenkinsfile

@@ -18,8 +18,6 @@ pipeline {
             sh 'cargo test --release'
           }
         }
-        stage('Builds') {
-          parallel {
         stage('Build Linux x86-64') {
           environment {
             PATH="/home/jenkins/.cargo/bin:$PATH"
@@ -60,7 +58,7 @@ pipeline {
           steps {
             sh 'cd docs ; xelatex manual.tex ; xelatex manual.tex'
           }
-        }}}
+        }
         stage('Malware scan') {
           steps {
             sh 'clamscan -r -i /home/jenkins/workspace'