Don't use bundled OpenSSL for tests - it fails to build on Alpine.
This patch fixes the following error:

error: failed to run custom build command for `openssl-sys v0.9.60`

Caused by:
  process didn't exit successfully: `/home/jirutjak/aports/testing/xh/src/xh-0.9.0/target/release/build/openssl-sys-97034bc2d62d9cd0/build-script-main` (exit code: 101)
  --- stdout
  cargo:rustc-cfg=const_fn
  cargo:rerun-if-env-changed=X86_64_ALPINE_LINUX_MUSL_OPENSSL_NO_VENDOR
  X86_64_ALPINE_LINUX_MUSL_OPENSSL_NO_VENDOR unset
  cargo:rerun-if-env-changed=OPENSSL_NO_VENDOR
  OPENSSL_NO_VENDOR unset

  --- stderr
  thread 'main' panicked at 'don't know how to configure OpenSSL for x86_64-alpine-linux-musl', /home/jirutjak/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-src-111.14.0+1.1.1j/src/lib.rs:219:18
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

--- a/Cargo.toml
+++ b/Cargo.toml
@@ -46,7 +46,7 @@
 indoc = "1.0"
 predicates = "1.0.7"
 httpmock = "0.5.5"
-curl = { version = "0.4.34", features = ["static-ssl"] }
+curl = { version = "0.4.34" }
 tempfile = "3.2.0"
 
 [features]
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1368,15 +1368,6 @@
 checksum = "28988d872ab76095a6e6ac88d99b54fd267702734fd7ffe610ca27f533ddb95a"
 
 [[package]]
-name = "openssl-src"
-version = "111.15.0+1.1.1k"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1a5f6ae2ac04393b217ea9f700cd04fa9bf3d93fae2872069f3d15d908af70a"
-dependencies = [
- "cc",
-]
-
-[[package]]
 name = "openssl-sys"
 version = "0.9.63"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1385,7 +1376,6 @@
  "autocfg",
  "cc",
  "libc",
- "openssl-src",
  "pkg-config",
  "vcpkg",
 ]