Revert "Fix error "callback is not a function" tarmolov#25"

This reverts commit 47f76df.

Author: tarmolov

lib/git-hooks.js

@@ -122,15 +122,6 @@ module.exports = {
         var hookName = path.basename(filename);
         var hooksDirname = path.resolve(path.dirname(filename), '../../.githooks', hookName);
 
-        // workaround for backward copmatibility
-        // npm 3.x doesn't execute preuninstall script
-        // @see https://github.com/npm/npm/issues/13963
-        args = [].concat(args) || [];
-        if (typeof input === 'function') {
-            callback = input;
-            input = '';
-        }
-
         if (fsHelpers.exists(hooksDirname)) {
             var list = fs.readdirSync(hooksDirname);
             var hooks = list.map(function (hookName) {