Retest scripts

[RichardWarburton]

@neomatrix369 reported that he was getting the following errors when running scripts:

readlink: illegal option -- f
usage: readlink [-n] [file …]

[FauxFaux]

Since 3a7c62c, the scripts are pretty broken on Debian/Ubuntu.

Their "alternatives" system means there's multiple layers of symlinks in front of javac:

% readlink $(which javac)
/etc/alternatives/javac
% readlink -f $(which javac)     
/usr/lib/jvm/java-8-oracle/bin/javac

This is what the readlink -f was resolving.

Additionally, the refactor broke the sed expression by moving the concatenation before the edit:

java_home=$(echo ${java_path}../ | sed 's/javac$//'.

[cinquin]

I didn't realize my commit broke things under Linux, but please note that we're now just back to a state where things are broken under OS X instead (as pointed out in issue #207).