Changed: Display a warning when a environment variable doesn't exist

--HG--
branch : develop

code/nel/src/misc/common.cpp

@@ -1033,6 +1033,7 @@ std::string expandEnvironmentVariables(const std::string &s)
 			{
 				// value not found
 				found = false;
+				nlwarning("Environment variable '%s' not found, won't be replaced", name.c_str());
 			}
 		}