We must check that the printed version is the correct one.

[mgautierfr]

Last change in the unit test removes hard coded version in the test. But then we don't test the version itself.

See #283 (comment)_ posted by @veloman-yunkan :

This change means that we don't care about the version string in the zimcheck output (since we test the contents of the VERSION macro via itself). Consider that the VERSION macro is carelessly redefined (#undefed and then #defined) by a header file included after zim-tools/src/version.h. Then our tests will not detect that.

This comment also applies to an earlier commit 409824a (in #208) but then we at least had a fallback in the form of this kind of checks.

I think we should preserve the version in an explicit textual form in at least one place (and better in three - output of zimcheck -v, version info in plaintext output and version info in JSON output).