tools: pass constant to logger instead of string
tools: pass constant to logger instead of string

On a few of our installations (namely CentOS), passing 'INFO'
resulted in a silent loglevel. Use a logging constant instead.

Fixes: https://github.com/nodejs/build/issues/104
PR-URL: https://github.com/nodejs/io.js/pull/1842
Reviewed-By: Rod Vagg <f9f03903429036ef609ed7ca822fddfa76155c29@vagg.org>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node