Fix raise to use Exception instead of raw strings

win_toolchain/package_from_installed.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 From a system-installed copy of the toolchain, packages all the required bits
 into a .zip file.
 
 It assumes default install locations for tools, in particular:
 - C:\Program Files (x86)\Microsoft Visual Studio 12.0\...
@@ skipping 299 matching lines @@
           zf.write(disk_name, archive_name)
       else:
         missing_files = True
         sys.stdout.write('\r%s does not exist.\n\n' % disk_name)
         sys.stdout.flush()
   if options.dryrun:
     sys.stdout.write('\r%1.3f GB of data in %d files, %d files for %s.%s\n' %
         (total_size / 1e9, count, version_match_count, WIN_VERSION, ' '*50))
     return 0
   if missing_files:
-    raise 'One or more files were missing - aborting'
+    raise Exception('One or more files were missing - aborting')
   if version_match_count == 0:
-    raise 'No files found that match the specified winversion'
+    raise Exception('No files found that match the specified winversion')
   sys.stdout.write('\rWrote to %s.%s\n' % (output, ' '*50))
   sys.stdout.flush()
 
   RenameToSha1(output)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())