Use with statement for file writing

[chris-lesage]

In https://github.com/mgear-dev/mgear4/blob/master/release/scripts/mgear/shifter/__init__.py

In the method data_collector_output()

f = open(file_path, "w")
f.write(json.dumps(self.build_data, indent=4))
f.close()
file_path = None

Should be rewritten as the safer and recommended with statement:

with open(file_path, 'w') as f:
    f.write(json.dumps(self.build_data, indent=4))
file_path = None

[miquelcampos]

Thanks @chris-lesage I will review this