Exit on mapper call failure

Sometimes we come up too fast and the mapper isn't ready.
Exit in this case so that systemd restarts us.

Change-Id: Icaaec9c40ced0fc975149db37b01cc65d5b7244c
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/src/EntityManager.cpp b/src/EntityManager.cpp
index e490420..9f95d0e 100644
--- a/src/EntityManager.cpp
+++ b/src/EntityManager.cpp
@@ -147,7 +147,9 @@
                        "available\n";
                 if (interfaceConnections.empty())
                 {
-                    return;
+                    // if we can't get the mapper data on the first run,
+                    // something is very wrong
+                    std::exit(EXIT_FAILURE);
                 }
             }
             else