Make Python interpreter selectable for test scripts
Make Python interpreter selectable for test scripts

The Python interpreter used to run the test cases is hard-coded to be
/usr/bin/python. If we use the first one from $PATH instead, it is
much easier to test ganeti with other Python versions.

Signed-off-by: Iustin Pop <acf83a5274f31a43af6b914614365999469c1a31@google.com>
Reviewed-by: Iustin Pop <acf83a5274f31a43af6b914614365999469c1a31@google.com>

dimara/ganeti,grnet/snf-ganeti,bitemyapp/ganeti,leshchevds/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,mbakke/ganeti,andir/ganeti,apyrgio/ganeti,bitemyapp/ganeti,yiannist/ganeti,onponomarev/ganeti,dimara/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,yiannist/ganeti,apyrgio/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,grnet/snf-ganeti,yiannist/ganeti,ganeti/ganeti,onponomarev/ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,andir/ganeti,ganeti/ganeti,leshchevds/ganeti,leshchevds/ganeti