Fix deploy script

[gitsparky]

Fix bugs and cleanup parity-deploy.sh and clean.sh

• Remove extra shift that broke parsing of ethstats and enable-client options
• Fix incorrect use of ">" instead of "-gt"
• Use proper bash-isms (-z and -n) for testing empty strings
• Use temp file instead of making a change & reverting the example.spec file
• Fix clean.sh not removing the .env file