I'd like to eliminate proxy.config.http.verbose_via_str

[Leif Hedstrom]

As per the discussions and patch provided on 
https://issues.apache.org/jira/browse/TS-973, I'd like to eliminate this 
configuration entirely:

    CONFIG proxy.config.http.verbose_via_str INT 2

Instead, the semantic of "verbosity" is moved to the two configurations 
related to enabling inserting Via: headers:

   # The via settings have three values
   #  0 - Do not modify / set this via header
   #  1 - Update the via, with normal verbosity
   #  2 - Update the via, with higher verbosity
 CONFIG proxy.config.http.insert_request_via_str INT 1
 CONFIG proxy.config.http.insert_response_via_str INT 0


Take a look at the patch, if I hear no objections, I'll make this change 
Monday next week.

-- Leif