opentelemetry: revert "opentelemetry: disable default tracing-log feature (#1869)" (#1882)

This reverts commit 2f10453.

Author: jtescher

tracing-opentelemetry/Cargo.toml

@@ -19,6 +19,9 @@ license = "MIT"
 edition = "2018"
 rust-version = "1.46.0"
 
+[features]
+default = ["tracing-log"]
+
 [dependencies]
 opentelemetry = { version = "0.17", default-features = false, features = ["trace"] }
 tracing = { path = "../tracing", version = "0.2", default-features = false, features = ["std"] }