python::requirements Error: Parameter cwd failed on Exec for virtualenv=system

[salimane]

while using

python::requirements { "${home_dir}/pip.requirements.txt":
        virtualenv => 'system',
        require => File["${home_dir}/pip.requirements.txt"]
}

I get the following errors

Error: Parameter cwd failed on Exec[python_requirements_update_/home/salimane/pip.requirements.txt]: cwd must be a fully qualified path

command not found `which

This pr fix those errors
Thanks

[stankevich]

Thanks!