Change formula to always pass explicit --enable-rubyecasound=<yes|no>
so it works regardless of the ecasound configure's default behavior
for --enable-ruby. Formula was assuming default was no, but default was
actually yes, so the ruby stuff got built even when --with-ruby was
not supplied, which could break the build when attempting to install
in to /Library/Ruby.
FixesHomebrew/homebrew#19357.
ClosesHomebrew/homebrew#19420.
Signed-off-by: Jack Nagel <jacknagel@gmail.com>
