[vault] clear() gets option ignore_snapshots

This option is added for additional safety: user should explicitely
request to delete storage if it has snapshots

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>

Merge pull request #10 from nemomobile/delete-vault

[vault] method to clear repository

[vault] ensure service files are always ignored

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>

[vault] add exclude when upgrading repository tree

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>

[vault] fix: write state only for existing repository

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>

Merge pull request #9 from deztructor/master

vault version check and state tracking

Merge pull request #8 from deztructor/master

VAULT_GLOBAL_CONFIG_DIR and "absent" status

Merge pull request #7 from deztructor/master

[unit] nor data, nor blobs are required

Merge pull request #6 from deztructor/master

fixed some string bin/data path processing

[vault] enforce checkout during related operation execution

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>