fix: pass GnuPG passphrase to duplicity to fix cleanup of mysql backups.

Correction for 9b6a82d commit.

The error was:
/usr/lib/python2.7/getpass.py:83: GetPassWarning: Can not control echo on the terminal.
  passwd = fallback_getpass(prompt, stream)
Warning: Password input may be echoed.
GnuPG passphrase for decryption: Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1532, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1526, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1380, in main
    do_backup(action)
  File "/usr/bin/duplicity", line 1401, in do_backup
    sync_archive(decrypt)
  File "/usr/bin/duplicity", line 1180, in sync_archive
    globals.gpg_profile.passphrase = get_passphrase(1, "sync")
  File "/usr/bin/duplicity", line 198, in get_passphrase
    pass1 = getpass_safe(_("GnuPG passphrase for decryption:") + " ")
  File "/usr/bin/duplicity", line 93, in getpass_safe
    return getpass.getpass(message)
  File "/usr/lib/python2.7/getpass.py", line 83, in unix_getpass
    passwd = fallback_getpass(prompt, stream)
  File "/usr/lib/python2.7/getpass.py", line 118, in fallback_getpass
    return _raw_input(prompt, stream)
  File "/usr/lib/python2.7/getpass.py", line 135, in _raw_input
    raise EOFError
EOFError

Fix #1157

[skip ci]

Author: php-coder

vagrant/provisioning/roles/mystamps-backup/templates/remote-backup.sh

@@ -25,7 +25,7 @@ case "${1:-}" in
 	'mysql-backups')
 		PASSPHRASE="$PASSPHRASE" su mystamps 2>&1 \
 			-c "${DUPLICITY_CMD} --name=mysql-backups /data/backups ${MYSQL_BACKUPS_DST}"
-		su mystamps 2>&1 \
+		PASSPHRASE="$PASSPHRASE" su mystamps 2>&1 \
 			-c "duplicity remove-all-but-n-full 3 --force ${MYSQL_BACKUPS_DST}"
 		;;
 	*)