Fix create_installer_archive.py to be more flexible with output directory names

chrome/installer/mini_installer.gyp

 {
   'variables': {
     'version_py': '../../chrome/tools/build/version.py',
     'version_path': '../../chrome/VERSION',
     'lastchange_path': '<(DEPTH)/build/util/LASTCHANGE',
     # 'branding_dir' is set in the 'conditions' section at the bottom.
     'msvs_use_common_release': 0,
     'msvs_use_common_linker_extras': 0,
     'mini_installer_internal_deps%': 0,
     'mini_installer_official_deps%': 0,
@@ skipping 217 matching lines @@
                     '<(PRODUCT_DIR)/ppGoogleNaClPluginChrome.dll',
                     '<(PRODUCT_DIR)/nacl_irt_x86_32.nexe',
                     '<(PRODUCT_DIR)/nacl_irt_x86_64.nexe',
                   ],
                 }],
                 ['target_arch=="x64"', {
                   'inputs!': [
                     '<(PRODUCT_DIR)/nacl64.exe',
                     '<(PRODUCT_DIR)/nacl_irt_x86_32.nexe',
                   ],
+                  'variables': {
+                    'target_arch_flag': '--target_arch=x64',
+                  },
+                }, {
+                  'variables': {
+                    'target_arch_flag': '--target_arch=x86',
+                  },
                 }],
               ],
               'inputs': [
                 '<(create_installer_archive_py_path)',
                 '<(PRODUCT_DIR)/app_host.exe',
                 '<(PRODUCT_DIR)/chrome.exe',
                 '<(PRODUCT_DIR)/chrome.dll',
                 '<(PRODUCT_DIR)/nacl64.exe',
                 '<(PRODUCT_DIR)/ppGoogleNaClPluginChrome.dll',
                 '<(PRODUCT_DIR)/nacl_irt_x86_32.nexe',
@@ skipping 12 matching lines @@
               'action': [
                 'python',
                 '<(create_installer_archive_py_path)',
                 '--build_dir', '<(PRODUCT_DIR)',
                 '--staging_dir', '<(INTERMEDIATE_DIR)',
                 '--input_file', '<(RULE_INPUT_PATH)',
                 '--resource_file_path', '<(INTERMEDIATE_DIR)/packed_files.rc',
                 '<(enable_hidpi_flag)',
                 '<(enable_touch_ui_flag)',
                 '<(component_build_flag)',
+                '<(target_arch_flag)',
                 # TODO(sgk):  may just use environment variables
                 #'--distribution=$(CHROMIUM_BUILD)',
                 '--distribution=_google_chrome',
                 # Optional arguments to generate diff installer
                 #'--last_chrome_installer=C:/Temp/base',
                 #'--setup_exe_format=DIFF',
                 #'--diff_algorithm=COURGETTE',
               ],
               'message': 'Create installer archive',
               'msvs_cygwin_shell': 1,
             },
           ],
         },
       ],
     }],
     [ 'branding == "Chrome"', {
       'variables': {
          'branding_dir': '../app/theme/google_chrome',
       },
     }, { # else branding!="Chrome"
       'variables': {
          'branding_dir': '../app/theme/chromium',
       },
     }],
   ],
 }