Add the /bin/bash shebang to build.sh (#1177)

Signed-off-by: Jose Luis Rivero <[email protected]>

jenkins-scripts/docker/lib/docker_generate_dockerfile.bash

@@ -145,6 +145,7 @@ fi
 
 echo '# BEGIN SECTION: create the Dockerfile'
 cat > Dockerfile << DELIM_DOCKER
+#!/bin/bash
 #######################################################
 # Docker file to run build.sh