Fix MSRV check (#1393)

Author: isabelatkinson

.evergreen/compile-only.sh

@@ -16,7 +16,15 @@ fi
 cargo $TOOLCHAIN build
 
 # Test with all features.
-cargo $TOOLCHAIN build --all-features
+if [ "$RUST_VERSION" != "" ]; then
+  cargo $TOOLCHAIN build --features openssl-tls,sync,aws-auth,zlib-compression,zstd-compression,snappy-compression,in-use-encryption,tracing-unstable
+else
+  cargo $TOOLCHAIN build --all-features
+fi
 
 # Test with no default features.
-cargo $TOOLCHAIN build --no-default-features --features compat-3-3-0,bson-3,rustls-tls
+if [ "$RUST_VERSION" != "" ]; then
+  cargo $TOOLCHAIN build --no-default-features --features compat-3-0-0,rustls-tls
+else
+  cargo $TOOLCHAIN build --no-default-features --features compat-3-3-0,bson-3,rustls-tls
+fi