Error condition not clear when docker version is less than required value.

[rtizzy]

Expected Behavior

Goldstone server should indicate that it failed due to an unmet/insufficient version requirement for Docker

Current Behavior

Attempting to start the server provides no output. Utilizing the status command leads to the following output. The output does not indicate that an insufficient version of docker is the issue.

goldstone-server.service - Goldstone Server
   Loaded: loaded (/usr/lib/systemd/system/goldstone-server.service; disabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Thu 2016-06-09 21:20:45 UTC; 3min 50s ago
  Process: 20889 ExecStop=/opt/goldstone/bin/docker-compose --verbose -f /opt/goldstone/docker-compose.yml stop (code=exited, status=1/FAILURE)
  Process: 20880 ExecStart=/opt/goldstone/bin/docker-compose --verbose -f /opt/goldstone/docker-compose.yml up (code=exited, status=1/FAILURE)
  Process: 20878 ExecStartPre=/sbin/iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu (code=exited, status=0/SUCCESS)
  Process: 20877 ExecStartPre=/sbin/iptables -D FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu (code=exited, status=0/SUCCESS)
 Main PID: 20880 (code=exited, status=1/FAILURE)

Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: goldstone-server.service: control process exited, code=exited status=1
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: Unit goldstone-server.service entered failed state.
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: goldstone-server.service failed.
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: goldstone-server.service holdoff time over, scheduling restart.
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: start request repeated too quickly for goldstone-server.service
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: Failed to start Goldstone Server.
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: Unit goldstone-server.service entered failed state.
Jun 09 21:20:45 osc1.solinea.com.localdomain systemd[1]: goldstone-server.service failed.

Possible Solution

If Docker is of an insufficient version this would ideally be indicated by systemctl status and logged to the goldstone log directory.

Steps to Reproduce (for bugs)

1. Install docker <1.10.0
2. Install Goldstone server
3. Start Goldstone server
4. Check status of Goldstone server with systemctl.

Context

Logging useful error messages aids in troubleshooting issues