[EC2] Adjust fs.file-max

From Robert Gibbon up on hbase-user@:

Maybe you are running Red Hat? Just changing limits.conf I think won't
work because RH has a maximum total open files across the whole system,
which is 4096 by default, unless you do something like this too

echo "32768" > /proc/sys/fs/file-max
service network restart

To make it permanent edit /etc/sysctl.conf to include the line:
fs.file-max = 32768

Update the remote init script appropriately.