Don't run cabal check on travis-ci

cabal check fails when using -O2.

Author: tibbe

.travis.yml

@@ -25,7 +25,6 @@ script:
  - cabal-1.18 configure --enable-tests -v2  # -v2 provides useful information for debugging
  - cabal-1.18 build   # this builds all libraries and executables (including tests/benchmarks)
  - cabal-1.18 test
- - cabal-1.18 check
  - cabal-1.18 sdist   # tests that a source-distribution can be generated
 
 # The following scriptlet checks that the resulting source distribution can be built & installed