python3: cpu-reformat: Use the print() function

Replace the print statement, that is only available in Py2, with a
print function that is available in both Py2 and Py3 and drop the
explicit python version in the shebang.
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>
Signed-off-by: NRadostin Stoyanov <rstoyanov1@gmail.com>

tests/cputestdata/cpu-reformat.py

-#!/usr/bin/env python2
+#!/usr/bin/env python
 
 import sys
 import json
@@ -6,4 +6,4 @@ import json
 dec = json.JSONDecoder()
 data, pos = dec.raw_decode(sys.stdin.read())
 json.dump(data, sys.stdout, indent=2, separators=(',', ': '))
-print
+print("\n")