path: don't lower-cases drive letters

In general path functions don't change the case of a path. Making an
exception for windows drive letters violates the principle of least
surprise.

Changing the drive letter case has caused a lot of issues, including
joyent/node#7031, joyent/node#7806 and lots of bikeshedding about
whether uppercase is the right case or lowercase.

This effectively reverts joyent/node@a05f973

Reviewed-by: Alexis Campailla <alexis@janeasystems.com>
Reviewed-by: Julien Gilli <julien.gilli@joyent.com>

lib/path.js

@@ -153,12 +153,6 @@ win32.resolve = function() {
   resolvedTail = normalizeArray(resolvedTail.split(/[\\\/]+/),
                                 !resolvedAbsolute).join('\\');
 
-  // If device is a drive letter, we'll normalize to lower case.
-  if (resolvedDevice && resolvedDevice.charAt(1) === ':') {
-    resolvedDevice = resolvedDevice[0].toLowerCase() +
-        resolvedDevice.substr(1);
-  }
-
   return (resolvedDevice + (resolvedAbsolute ? '\\' : '') + resolvedTail) ||
          '.';
 };
@@ -172,11 +166,6 @@ win32.normalize = function(path) {
       tail = result[3],
       trailingSlash = /[\\\/]$/.test(tail);
 
-  // If device is a drive letter, we'll normalize to lower case.
-  if (device && device.charAt(1) === ':') {
-    device = device[0].toLowerCase() + device.substr(1);
-  }
-
   // Normalize the tail path
   tail = normalizeArray(tail.split(/[\\\/]+/), !isAbsolute).join('\\');
 

test/simple/test-module-nodemodulepaths.js

@@ -21,7 +21,6 @@
 
 var common = require('../common');
 var assert = require('assert');
-var path = require('path');
 
 var module = require('module');
 
@@ -30,7 +29,7 @@ var isWindows = process.platform === 'win32';
 var file, delimiter, paths;
 
 if (isWindows) {
-  file = path.normalize('C:\\Users\\Rocko Artischocko\\node_stuff\\foo');
+  file = 'C:\\Users\\Rocko Artischocko\\node_stuff\\foo';
   delimiter = '\\'
 } else {
   file = '/usr/test/lib/node_modules/npm/foo';

test/simple/test-path.js

@@ -311,7 +311,7 @@ if (isWindows) {
        [['c:/ignore', 'd:\\a/b\\c/d', '\\e.exe'], 'd:\\e.exe'],
        [['c:/ignore', 'c:/some/file'], 'c:\\some\\file'],
        [['d:/ignore', 'd:some/dir//'], 'd:\\ignore\\some\\dir'],
-       [['.'], path.normalize(process.cwd())],
+       [['.'], process.cwd()],
        [['//server/share', '..', 'relative\\'], '\\\\server\\share\\relative'],
        [['c:/', '//'], 'c:\\'],
        [['c:/', '//dir'], 'c:\\dir'],