Drop clunky '+' naming convention that doesn't play nicely in S3 deb rep...

...o.

Getting artifacts ready to go out the door with beta2.  Clean up the description a tad.

Before: 	serviced_0.3.70+0.8.0-591~trusty_amd64.deb
After:        serviced_0.8.0-592~trusty_amd64.deb

Avoiding some of this angst: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1003633