Try this may be it will work.
Code:
<IfModule mod_setenvif.c>
SetEnvIfNoCase User-Agent ^us-west-2.compute.amazonaws.com bad_bot
SetEnvIfNoCase User-Agent ^compute.amazonaws.com bad_bot
SetEnvIfNoCase User-Agent ^amazonaws.com bad_bot
SetEnvIfNoCase User-Agent ^compute-1.amazonaws.com bad_bot
SetEnvIfNoCase User-Agent ^us-west-2.compute.amazonaws.com bad_bot
SetEnvIfNoCase User-Agent ^.us-west-2.compute.amazonaws.com bad_bot
<Limit GET POST PUT>
Order Allow,Deny
Allow from all
Deny from env=bad_bot
</Limit>
</IfModule>