Delete Cargo.lock
Delete Cargo.lock

Since exonum itself and any other crates in this repository are libraries (not application), `Cargo.lock` file must be unspecified.

Former-commit-id: 606f72e45b9146cc00e823fe00e02198fa04b5ad
alekseysidorov/exonum,exonum/exonum,alekseysidorov/exonum,exonum/exonum,alekseysidorov/exonum,exonum/exonum,alekseysidorov/exonum,exonum/exonum