[chef_fs/file_system] Ignore missing entry at destination when purging

If a user attempts to call #copy_to with a path that does not exist at
either the source or destination and :purge set to true, we currently
fail with an error trying to delete the non-existent entry at the
destination.

This patch ignores that failure.
remove setting proxy environment variables
Merge pull request #1519 from opscode/ssd/purge-ignore-missing-on-purge

[chef_fs/file_system] Ignore missing entry at destination when purging
Merge pull request #1526 from opscode/mcquin/windows_service

remove setting proxy environment variables
[CHEF-5158] knife[:attribute] in knife.rb should not override --attribute in the command line
CHEF-5158: Make the former override_attribute's purpose a bit more clear
CHEF-5158: Add some debugging information for knife ssh attribute
CHEF-5158: Contribution notes
CHEF-5287: Use IsWow64Process instead of ENV hash to determine 32-bit process on 64-bit OS
Fix undefined Windows constants on non-Windows platforms
Restore check for Windows platform in windows_architecture_helper to fix spec break on non-Windows
CHEF-5287 Change log update
Merge pull request #1531 from opscode/adamed/chef-5287-rebase

CHEF-5287: batch resource: can't convert nil into String due to invalid ENV hash
Merge pull request #1530 from opscode/btm/CHEF-5158

CHEF-5158: Prefer CLI argument over configuration file setting for ssh_attribute
Bump ffi version since chef-dk depends on chef and dep-selector and dep-selector uses ~> 1.9.
Use FFI::LastError instead of GetLastError for ffi 1.9.x compatibility.
Fix windows specs.
Misc spec fixes for windows.