FindGit: Cache the version more effectively
In !5712 (merged), the
GIT_VERSION_STRING was meant to be cached after the first time it was computed for a given
GIT_EXECUTABLE location. That logic assumed
GIT_VERSION_STRING would be visible in the current scope, but it might not be. The global property alone is enough to check whether the version has been determined previously, so don't switch the logic based on whether
GIT_VERSION_STRING is defined or not.