test init: remove a couple of paranoid sanity checks * t/ax/test-init.sh: Here, about 'am_top_srcdir' and 'am_top_builddir'; the values of those variables are AC_SUBST'd, so it's nigh impossible for the to be wrong or get "messed up". Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>