EntityManager: Clean up interface removal condition

The early exit only serves to decrease readability by negating a
condition and adding more lines. Instead, add another negation and
remove a line.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I3c2dc571b4fe7b1c763f5951c64e35d43b77ce0a
diff --git a/src/EntityManager.cpp b/src/EntityManager.cpp
index e484af7..173f4dc 100644
--- a/src/EntityManager.cpp
+++ b/src/EntityManager.cpp
@@ -983,11 +983,10 @@
                     for (auto& iface : ifaces)
                     {
                         auto sharedPtr = iface.lock();
-                        if (!sharedPtr)
+                        if (!!sharedPtr)
                         {
-                            continue; // was already deleted elsewhere
+                            objServer.remove_interface(sharedPtr);
                         }
-                        objServer.remove_interface(sharedPtr);
                     }
                     ifaces.clear();
                     systemConfiguration.erase(name);