fix typo in the build script

Change-Id: Ia93c99c2209c84981e0b3d30b968db74ebed99d2
diff --git a/Jenkinsfile-voltha-build b/Jenkinsfile-voltha-build
index cb7552e..d4fd9bf 100644
--- a/Jenkinsfile-voltha-build
+++ b/Jenkinsfile-voltha-build
@@ -313,7 +313,7 @@
                 }
             }
             if ( params.inBandManagement ) {
-                stage('Reboot OLT’) {
+                stage('Reboot OLT') {
                     for(int i=0; i < deployment_config.olts.size(); i++) {
                         timeout(5) {
                             sh returnStdout: true, script: """