fix build Solr, failed in https://travis-ci.org/laradock/laradock/jobs/479960032 (#1957)

solr/Dockerfile

@@ -18,7 +18,7 @@ ENV SOLR_DATAIMPORTHANDLER_MSSQL ${SOLR_DATAIMPORTHANDLER_MSSQL}
 # download mssql connector for dataimporthandler
 RUN if [ ${SOLR_DATAIMPORTHANDLER_MSSQL} = true ]; then \
     curl -L -o /tmp/mssql-jdbc-7.0.0.jre8.jar "https://github.com/Microsoft/mssql-jdbc/releases/download/v7.0.0/mssql-jdbc-7.0.0.jre8.jar" \
-       && mkdir /opt/solr/contrib/dataimporthandler/lib \
+       && mkdir -p /opt/solr/contrib/dataimporthandler/lib \
        && mv /tmp/mssql-jdbc-7.0.0.jre8.jar "/opt/solr/contrib/dataimporthandler/lib/mssql-jdbc-7.0.0.jre8.jar" \
 ;fi