Revert 273108 "Omaha configuration parameters now use Wow6432Nod..."

> Omaha configuration parameters now use Wow6432Node (32-bit registry) on 64-bit installs.  GCAPI configuration parameters also use these same accesses since they read/write the same data.
> 
> Also, force installation of Win64 into C:\Program Files (x86) until the code is added to support moving the files to the right place during upgrade and downgrade.  Uninstall information will remain stored in the 32-bit registry (even on 64-bit) until the installation location is changed.
> 
> This fixes system installs on Win64.
> 
> BUG=338706
> R=grt@chromium.org
> 
> Review URL: https://codereview.chromium.org/300593002

TBR=wfh@chromium.org

Review URL: https://codereview.chromium.org/297233010

git-svn-id: svn://svn.chromium.org/chrome/branches/2017/src@273138 0039d316-1c4b-4281-b951-d872f2087c98
18 files changed