Support for building on older cmake versions
Support for building on older cmake versions

Backported python cmake module expects at least cmake 3.7 (requested
by policy), which will break builds on older cmake versions, like 3.5.

This fix will omit python module inclusion for any cmake version less
than 3.7 and the build will continue without problems.

ledger/ledger,ledger/ledger,ledger/ledger,afh/ledger,ledger/ledger,ledger/ledger,afh/ledger,afh/ledger,afh/ledger,afh/ledger