Keep the storage alive in Router group management.

When initializing or refreshing the routing groups, keep the storage reference
alive so that we won't re-initialize it for every group we got from the group
lists.

Backport from master:70fee3

Signed-off-by: Denis Zaitsev <oktocat@yandex.com>
changelog bump

Signed-off-by: Denis Zaitsev <oktocat@yandex.com>
Merge pull request #106 from oktocat/v0.11

Keep the storage alive in Router group management.