Don't build the RPMs for ChromeOS.

chrome/installer/installer.gyp

 {
   'variables': {
     'version_py': '../../chrome/tools/build/version.py',
     'version_path': '../../chrome/VERSION',
     'lastchange_path': '<(SHARED_INTERMEDIATE_DIR)/build/LASTCHANGE',
     # 'branding_dir' is set in the 'conditions' section at the bottom.
   },
   'conditions': [
     ['OS=="win"', {
       'targets': [
@@ skipping 550 matching lines @@
                 '<(deb_build)',
                 '<@(input_files)',
               ],
               'outputs': [
                 '<(PRODUCT_DIR)/google-chrome-<(channel)_<(version)-r<(revision)_<(deb_arch).deb',
               ],
               'action': [ '<@(deb_cmd)', '-c', '<(channel)', ],
             },
           ],
           'conditions': [
-            ['target_arch=="ia32"', {
+            ['target_arch=="ia32" and chromeos==0', {
               'actions': [
                 {
                   'variables': {
                     'channel': 'unstable',
                   },
                   'action_name': 'rpm_packages_<(channel)',
                   'process_outputs_as_sources': 1,
                   'inputs': [
                     '<(rpm_build)',
                     '<(PRODUCT_DIR)/installer/rpm/chrome.spec.template',
@@ skipping 49 matching lines @@
       'variables': {
          'branding_dir': '../app/theme/google_chrome',
       },
     }, { # else branding!="Chrome"
       'variables': {
          'branding_dir': '../app/theme/chromium',
       },
     }],
   ],
 }