Don't force uppercase meta keys in env vars

client/driver/env/env.go

@@ -141,6 +141,7 @@ func (t *TaskEnvironment) Build() *TaskEnvironment {
 	// Build the meta
 	for k, v := range t.TaskMeta {
 		t.TaskEnv[fmt.Sprintf("%s%s", MetaPrefix, strings.ToUpper(k))] = v
+		t.TaskEnv[fmt.Sprintf("%s%s", MetaPrefix, k)] = v
 	}
 
 	// Build the ports

website/source/docs/runtime/environment.html.md

@@ -158,7 +158,9 @@ The job specification also allows you to specify a `meta` block to supply arbitr
 configuration to a task. This allows you to easily provide job-specific
 configuration even if you use the same executable unit in multiple jobs. These
 key-value pairs are passed through to the job as `NOMAD_META_<key>=<value>`
-environment variables, where `key` is UPPERCASED from the job specification.
+environment variables. Prior to Nomad 0.5.5 the key was uppercased and since
+then both the original case and an uppercased version are injected. The
+uppercased version will be deprecated in a future release.
 
 Currently there is no enforcement that the meta keys be lowercase, but using
 multiple keys with the same uppercased representation will lead to undefined