Add exit on error in solr entrypoint

Fixed #30

Author: mblaschke

docker/solr/entrypoint.sh

@@ -1,5 +1,9 @@
 #!/bin/bash
 
+set -o pipefail  # trace ERR through pipes
+set -o errtrace  # trace ERR through 'time command' and other functions
+set -o nounset   ## set -u : exit the script if you try to use an uninitialised variable
+set -o errexit   ## set -e : exit the script if any statement returns a non-true return value
 
 ###################
 # Move storage to storage container
@@ -27,4 +31,4 @@ if [ "$1" = 'solr' ]; then
     exec java -jar start.jar
 fi
 
-exec "$@"
+exec "$@"