clone: cleanup the "cleanup dir" logic used during local clone
With the previous code, there was a small windows were we could delete too much
data. This should no longer be the case.
(This is an opportunity improvement while looking at something next to that.)
Differential Revision: https://phab.mercurial-scm.org/D10840
{
// 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)
}