grep: don't look up copy info unless --follow is given
If no --follow was given, then the "copy" variable will become
None. In that case we would still look up the copy information from
the filelog and then ignore it. Let's avoid even looking it up.
Differential Revision: https://phab.mercurial-scm.org/D5620
{
// 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)
}