L2SS-218 Following Jan David's advice to just use sub-shells instead of pushd/popd

bootstrap/sbin/rebuild_system_from_scratch.sh

@@ -15,14 +15,12 @@ trap ' exit ${?} ' ABRT EXIT HUP INT TERM QUIT ERR
 
 function pull_images()
 {
-    pushd ${HOME_DIR}/docker-compose && make pull
-    popd
+    (cd ${HOME_DIR}/docker-compose && make pull)
 }
 
 function build_lofar_images()
 {
-    pushd ${HOME_DIR}/docker-compose && make build
-    popd
+    (cd ${HOME_DIR}/docker-compose && make build)
 }
 
 function move_tango_dir_out_of_the_way()
@@ -48,23 +46,21 @@ function clean_images()
     # has already been shut down.
     # Therefore disable Bash's exit on error flag
     set +e
-    pushd ${HOME_DIR}/docker-compose && make clean
-    popd
+    (cd ${HOME_DIR}/docker-compose && make clean)
     # And enable it again.
     set -e
 }
 
 function start_minimal_tango()
 {
-    pushd ${HOME_DIR}/docker-compose
+    (cd ${HOME_DIR}/docker-compose
     make minimal
     make start dsconfig
     # Just for good measure, wait a moment and start dsconfig again
     echo -e "\tWaiting for dsconfig to settle down..."
     sleep 10
     echo -e "\tDone.\n\tStarting dsconfig again."
-    make start dsconfig
-    popd
+    make start dsconfig)
 }
 
 function configure_tango_db()
@@ -77,23 +73,20 @@ function configure_tango_db()
 
 function configure_elk()
 {
-    pushd ${HOME_DIR}/docker-compose && make start elk-configure-host
-    popd
+    (cd ${HOME_DIR}/docker-compose && make start elk-configure-host)
 }
 
 function start_support_images()
 {
-    pushd ${HOME_DIR}/docker-compose && make start elk
-    make start jupyter
-    popd
+    (cd ${HOME_DIR}/docker-compose && make start elk
+    make start jupyter)
 }
 
 function start_lofar_images()
 {
-    pushd ${HOME_DIR}/docker-compose
+    (cd ${HOME_DIR}/docker-compose
     make start device-pcc
-    make start device-sdp
-    popd
+    make start device-sdp)
 }