Use openssl-probe (fix #161)

The distributed binaries are statically linked with OpenSSL, which means we have to use
openssl-probe in order to make sure they work on all systems.

Cargo.lock

@@ -1832,6 +1832,7 @@ dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "nix 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rust-ini 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "self_update 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)",

Cargo.toml

@@ -30,6 +30,7 @@ chrono = "0.4.6"
 tokio = "0.1.21"
 tokio-process = "0.2.3"
 futures = "0.1.27"
+openssl-probe = { version = "0.1.2", optional = true }
 
 [target.'cfg(unix)'.dependencies]
 nix = "0.14.0"
@@ -40,4 +41,4 @@ lto = true
 [features]
 default = []
 
-self-update = ["self_update_crate"]
+self-update = ["self_update_crate", "openssl-probe"]

src/main.rs

@@ -16,6 +16,8 @@ use self::steps::*;
 use self::terminal::*;
 use failure::{Fail, ResultExt};
 use log::debug;
+#[cfg(feature = "self-update")]
+use openssl_probe;
 use std::borrow::Cow;
 use std::env;
 use std::fmt::Debug;
@@ -84,6 +86,7 @@ fn run() -> Result<(), Error> {
 
     #[cfg(feature = "self-update")]
     {
+        openssl_probe::init_ssl_cert_env_vars();
         if !run_type.dry() && env::var("TOPGRADE_NO_SELF_UPGRADE").is_err() {
             if let Err(e) = self_update::self_update() {
                 print_warning(format!("Self update error: {}", e));