core: Network: misc code cleanups

Change-Id: Idc37b5f834220e8e980958953785806687435f36
Refs: #3858
diff --git a/core/network-interface-predicate.cpp b/core/network-interface-predicate.cpp
index abb0029..cf5fcd6 100644
--- a/core/network-interface-predicate.cpp
+++ b/core/network-interface-predicate.cpp
@@ -97,13 +97,12 @@
 static bool
 doesMatchRule(const NetworkInterfaceInfo& nic, const std::string& rule)
 {
-  // if / is in rule, this is a subnet, check if IP in subnet
-
-  if (boost::contains(rule, "/")) {
+  // if '/' is in rule, this is a subnet, check if IP in subnet
+  if (rule.find('/') != std::string::npos) {
     Network n = boost::lexical_cast<Network>(rule);
     for (const auto& addr : nic.ipv4Addresses) {
       if (n.doesContain(addr)) {
-          return true;
+        return true;
       }
     }
   }