[tlbuild] initial test builds for TL'15 (no commits)

[Karl Berry]

    usage: tail [+/-[n][lbc][f]] [file]
           tail [+/-[n][l][r|f]] [file]

Ah.  tail on Solaris 10 doesn't support the now-mandated POSIX syntax of
"tail -n+2" (or "tail -n +2").  And other systems refuse to handle the
once-universal "tail +2" because POSIX doesn't like it.  Once again
POSIX makes things less portable instead of more.  Anyway.

Anyway, I changed the test to use "sed 1,2d", which should work
everywhere (until future standards "improve" sed).

Thanks for the report,
k