Renumber flags version numbers in 'filterConfigureFlags'.
Renumber flags version numbers in 'filterConfigureFlags'.

Previously, the code was inconsistent on whether or not
flags_x_y_z indicated that these flags could be used
up to version x.y.z, or should be used prior to x.y.z.
This commit picks the LATTER and renames everything
consistently this way.  The bonus is that now the names
match up with the conditionals. Yay.

Signed-off-by: Edward Z. Yang <dbd597f5635f432486c5d365e9bb585b3eaa1853@cs.stanford.edu>

themoritz/cabal,mydaum/cabal,themoritz/cabal,mydaum/cabal,themoritz/cabal