generate_indy_pool_transactions can be run only by indy user

Steps to Reproduce:
1. Setup the machine with installed sovrin package.
2. Set yourself as any user differ from indy.
3. Try to generate transactions to connect to some test network:

generate_indy_pool_transactions --nodes 4 --clients 4 --ips '10.20.30.201,10.20.30.202,10.20.30.203,10.20.30.204'

Actual Results:
Permission denied error appear for file /etc/indy/indy_config.py, transaction file was not generated.

Expected Result:
generate_indy_pool_transactions should work without errors.

Additional Information:
Ticket priority is Highest because this problem appears in agent installation script for vagrant, so one performing GST is impossible on vagrant pool.

Problem is actual only for master version of vagrant scripts. Stable version of vagrant scripts work well.

Problem also reproduces on the latest version for not vagrant setup.