HTTParty permanently overrides default request headers of Net::HTTP

[qsona]

Version

httparty 0.13.7
(Ruby on Rails 4.2.6)

Reproduce Steps

1. HTTParty.get('http://httpstat.us/204', debug_output: $stdout)
   request log:
   <- "GET /204 HTTP/1.1\r\nAccept-Encoding: gzip;q=1.0,deflate;q=0.6,identity;q=0.3\r\nAccept: */*\r\nUser-Agent: Ruby\r\nConnection: close\r\nHost: httpstat.us\r\n\r\n"

2. HTTParty.get('http://httpstat.us/204', headers: {}, debug_output: $stdout)
   request log:
   <- "GET /204 HTTP/1.1\r\nConnection: close\r\nHost: httpstat.us\r\n\r\n"

3. HTTParty.get('http://httpstat.us/204', debug_output: $stdout)
   request log:
   <- "GET /204 HTTP/1.1\r\nConnection: close\r\nHost: httpstat.us\r\n\r\n"

On the second request, I specified headers: {} option, then the default headers (Accept-Encoding, Accept, User-Agent) are removed. And after that, even if I don't specified headers option, these headers don't come back.

[jnunemaker]

Closed by #518