[migration] re-try without print_function when compiling a script fails
As part of the python3 porting we added the __future__.print_function import to
cubicweb.migration. That started affecting all migration scripts it runs,
which may not be prepared. So if compiling a script results in SyntaxError,
try again without the print_function flag.
Closes #7935030
usr/lib/python2*/*-packages/cubicweb/devtools/
usr/lib/python2*/*-packages/cubicweb/skeleton/
usr/lib/python2*/*-packages/cubicweb/test
usr/lib/python2*/*-packages/cubicweb/entities/test
usr/lib/python2*/*-packages/cubicweb/ext/test
usr/lib/python2*/*-packages/cubicweb/server/test
usr/lib/python2*/*-packages/cubicweb/sobjects/test
usr/lib/python2*/*-packages/cubicweb/hooks/test
usr/lib/python2*/*-packages/cubicweb/web/test
usr/lib/python2*/*-packages/cubicweb/etwist/test