Ref labels in the commit details pane use the wrong colors #635

@hannesa2, two colour bugs in the commit details pane, both older than they look
and neither related to any current work. Found while working on #629.

1. The pane keeps its own palette, and it has drifted.
colorForRef: and Resources/html/views/history/history.css each carry
a hard-coded copy of the label colors, and they no longer agree:

So the same branch is one green in the list and a deeper green two inches below it.

2. The current branch never gets its orange there at all.
Its label is drawn green, like any other branch.
The rule exists and is correct; the class is never added, because
a ref reaches the page through WebScripting as a function:

if (commit.currentRef == ref.ref) {      // string == function, never true
	span.classList.add("currentBranch");
}

ref.type() and ref.shortName() on the next lines are called properly, so it
reads as correct at a glance. Probed in a debug build:

typeof ref.ref = function   called = refs/heads/master   currentRef = refs/heads/master

Called through, the two sides are identical.
git log -S dates the line to 6da0816c, so the orange has not worked in that pane for a long time...

Both are fixed in the first commit of #633, ahead of the worktree work that
found them, so they can be reviewed on their own. Gonen has screenshots of the
two glitches and will add them below.