Use `Cache-Control: max-age=0' instead of `no-cache'.

Varnish ignores `no-cache', and since `max-age=0' works just as well
for both Varnish and web browsers, and makes for simpler code, just
use that instead.
Remove extraneous space.

This fixes #247.
Updates to debian init script

 - support /etc/default/opentsdb
 - Add /usr/lib/default-java as a potential JDK path, this
   is commonly used as a symlink to the default jdk

Signed-off-by: Benoit Sigoure <tsunanet@gmail.com>
Provide a default value for os.name to avoid NPE in some cases.

Signed-off-by: Benoit Sigoure <tsunanet@gmail.com>