move getEnv methods into env namespace

Move the getEnv(...) methods into the env namespace,
for consistency.

Change-Id: I4055d9456c17f8b20071cdee1b8e531c10fb0c7e
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/thresholds.hpp b/thresholds.hpp
index 96d4b75..684e712 100644
--- a/thresholds.hpp
+++ b/thresholds.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "env.hpp"
+
 /** @class Thresholds
  *  @brief Threshold type traits.
  *
@@ -90,8 +92,8 @@
     auto& obj = std::get<Object>(info);
     std::shared_ptr<T> iface;
 
-    auto tLo = getEnv(Thresholds<T>::envLo, sensorType, sensorID);
-    auto tHi = getEnv(Thresholds<T>::envHi, sensorType, sensorID);
+    auto tLo = env::getEnv(Thresholds<T>::envLo, sensorType, sensorID);
+    auto tHi = env::getEnv(Thresholds<T>::envHi, sensorType, sensorID);
     if (!tLo.empty() && !tHi.empty())
     {
         iface = std::make_shared<T>(bus, objPath.c_str(), deferSignals);