Add another version of getEnv

The new version takes the type and ID parameters
separately as opposed to together in a key_type.

Change-Id: I7796e8e6d680ffb640028e91eb3dcc8e7d99bc2e
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/env.cpp b/env.cpp
index 5745e16..efd081b 100644
--- a/env.cpp
+++ b/env.cpp
@@ -39,6 +39,15 @@
     return value;
 }
 
+std::string getEnv(
+    const char* prefix,
+    const std::string& type,
+    const std::string& id)
+{
+    SensorSet::key_type sensor{type, id};
+    return getEnv(prefix, sensor);
+}
+
 std::string getIndirectLabelEnv(
     const char* prefix, std::string path, const SensorSet::key_type& sensor)
 {