bootstrap.sh: Update zlib version regexp.
bootstrap.sh: Update zlib version regexp.

randen/cabal,bennofs/cabal,lukexi/cabal,mydaum/cabal,kolmodin/cabal,headprogrammingczar/cabal,headprogrammingczar/cabal,randen/cabal,kolmodin/cabal,edsko/cabal,thomie/cabal,sopvop/cabal,gbaz/cabal,edsko/cabal,themoritz/cabal,Heather/cabal,martinvlk/cabal,bennofs/cabal,sopvop/cabal,themoritz/cabal,mydaum/cabal,garetxe/cabal,lukexi/cabal,gbaz/cabal,Heather/cabal,martinvlk/cabal,thomie/cabal,themoritz/cabal,garetxe/cabal,sopvop/cabal