fix build failure if snappy is missing
Merge pull request #16 from manuzhang/fix_build_failure_if_snappy_missing

fix build failure if snappy is missing
Revert "Merge pull request #16 from manuzhang/fix_build_failure_if_snappy_missing"

This reverts commit acee5d1743df98d341b73d987bcad799958c884c, reversing
changes made to a4038c2959abe4ad87b5eecbdf2f96065e84f438.