Configure structopt to report the right version

By default, structopt reports the value provided by
the env var CARGO_PKG_VERSION, feeded by Cargo when reading
Cargo.toml. However for Garage we use a versioning based on git,
so we often report a version that is behind the real version.
In this commit, we create garage_util::version::garage() that
reports the right version and configure all structopt subcommands
to call this function instead of using the env var.

src/rpc/Cargo.toml

@@ -19,7 +19,6 @@ garage_util = { version = "0.7.0", path = "../util" }
 arc-swap = "1.0"
 bytes = "1.0"
 gethostname = "0.2"
-git-version = "0.3.4"
 hex = "0.4"
 tracing = "0.1.30"
 rand = "0.8"

src/rpc/system.rs

@@ -27,6 +27,7 @@ use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::persister::Persister;
 use garage_util::time::*;
+use garage_util::version;
 
 use crate::consul::*;
 #[cfg(feature = "kubernetes-discovery")]
@@ -320,11 +321,7 @@ impl System {
 	//      also available through RPC) ----
 
 	pub fn garage_version(&self) -> &'static str {
-		option_env!("GIT_VERSION").unwrap_or(git_version::git_version!(
-			prefix = "git:",
-			cargo_prefix = "cargo:",
-			fallback = "unknown"
-		))
+		version::garage()
 	}
 
 	pub fn get_known_nodes(&self) -> Vec<KnownNodeInfo> {