httppeer: always add x-hg* headers to Vary header
Before, we manually updated the Vary header value for each
header contributing to it.
All X-Hg* headers are reserved for the Mercurial protocol and
could have caching implications. So it makes sense to always add
these headers to Vary.
A test revealed that X-HgArgs-Post wasn't being added to Vary.
This is only sent on POST requests. POST requests generally
aren't cacheable. However, it is possible if the server sends
the appropriate headers. Mercurial shouldn't be sending those
headers. But let's not take any chances.
Differential Revision: https://phab.mercurial-scm.org/D3240
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}