tools: Update run-dev.py to output right subdomain if on Zulip droplet.
tools: Update run-dev.py to output right subdomain if on Zulip droplet.

I have updated `tools/run-dev.py` to output the correct subdomain such as
`http://zulip.username.zulipdev.org` so that the user knows the correct
subdomain to access the Zulip Dev realm on.

andersk/zulip,eeshangarg/zulip,andersk/zulip,eeshangarg/zulip,hackerkid/zulip,zulip/zulip,kou/zulip,rht/zulip,zulip/zulip,rht/zulip,andersk/zulip,zulip/zulip,hackerkid/zulip,eeshangarg/zulip,hackerkid/zulip,zulip/zulip,punchagan/zulip,punchagan/zulip,andersk/zulip,eeshangarg/zulip,hackerkid/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip,zulip/zulip,punchagan/zulip,punchagan/zulip,andersk/zulip,hackerkid/zulip,kou/zulip,rht/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,punchagan/zulip,rht/zulip,andersk/zulip,kou/zulip,rht/zulip,kou/zulip,rht/zulip,punchagan/zulip,punchagan/zulip,kou/zulip,andersk/zulip,eeshangarg/zulip,hackerkid/zulip,kou/zulip