Fix stylistic problems with help text
Fix stylistic problems with help text

The help text for the backdoor_port configuration option was a little
groddy.  This reformats it to clean it up a little.  Some punctuation
is also added to clarify the meaning of the text.

Change-Id: Ie61be9f0d08cd9c2485177b207216b3b775acd04

JioCloud/oslo-incubator,JioCloud/oslo-incubator,JioCloud/oslo-incubator