MQ 9.1.5 image changes (#62)

* Upgraded to MQ 9.1.5, upgraded to unzippable install, run as random UID (1001 by default)

* Updated docker tests for MQ 915 random UID

* Added warning to crtmqdir for 10 rc, added trace option to crtmqdir

* Removed dev users from dockerfile

docs/usage.md

@@ -71,7 +71,7 @@ FROM ibmcom/mq
 USER root
 RUN useradd alice -G mqm && \
     echo alice:passw0rd | chpasswd
-USER mqm
+USER 1001
 COPY 20-config.mqsc /etc/mqm/
 ```