vk/glsl_scraper: Fix code style for imports

Python style is one module imported per line, and imports are at the top
of the file.

src/vulkan/glsl_scraper.py

@@ -1,5 +1,14 @@
 #! /usr/bin/env python
 
+import cStringIO
+import os
+import re
+import shutil
+import struct
+import subprocess
+import sys
+import tempfile
+
 def print_usage(err):
    print """\
 glsl_scraper.py [options] file
@@ -16,8 +25,6 @@ Options:
    --with-glslang=PATH  Full path to the glslangValidator program"""
    exit(err)
 
-import os, sys, re, cStringIO, tempfile, subprocess, struct, shutil
-
 class Shader:
    def __init__(self, stage):
       self.stream = cStringIO.StringIO()