Deploying from windows is broken

[ahgittin]

the BrooklynConfigKeys puts Os.tmp() into a freemarker template, but that results in an invalid / unparseable template on windows, probably because the temp dir has backslashes.

suggest we fix by hardcoding "/tmp/" -- it shouldn't be used in normal code paths in any case

[sjcorbett]

This should be fixed by the above commit.