fix: resolve folder that is passed in

Root cause of npm/cli#613

index.js

@@ -18,6 +18,7 @@ module.exports = BB.promisify(binLinks)
 
 function binLinks (pkg, folder, global, opts, cb) {
   pkg = normalize(pkg)
+  folder = path.resolve(folder)
 
   // if it's global, and folder is in {prefix}/node_modules,
   // then bins are in {prefix}/bin

test/link-bins.js

@@ -77,7 +77,10 @@ t.test('foo package cannot link, pre-existing stuff there', t => {
 })
 
 t.test('foo package can link with --force link', t => {
-  const foo = resolve(me, 'node_modules/foo')
+  const cwd = process.cwd()
+  t.teardown(() => process.chdir(cwd))
+  process.chdir(me)
+  const foo = 'node_modules/foo'
   mkdirp(foo)
   const pkg = {
     name: 'foo',