Require explicit decorator on one arg constructors

We essentially follow this rule already, not relying on implicit
operators, although there are a number of cases where in theory we
could've implicitly constructed an object.

This commit enables the clang-tidy check.

Tested: Code compiles, passes clang-tidy.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ia428463313b075c69614fdb326e8c5c094e7adde
diff --git a/redfish-core/include/event_service_manager.hpp b/redfish-core/include/event_service_manager.hpp
index 3c47698..1785828 100644
--- a/redfish-core/include/event_service_manager.hpp
+++ b/redfish-core/include/event_service_manager.hpp
@@ -374,7 +374,8 @@
         // Subscription constructor
     }
 
-    Subscription(const std::shared_ptr<boost::beast::tcp_stream>& adaptor) :
+    explicit Subscription(
+        const std::shared_ptr<boost::beast::tcp_stream>& adaptor) :
         eventSeqNum(1)
     {
         sseConn = std::make_shared<crow::ServerSentEvents>(adaptor);
diff --git a/redfish-core/include/privileges.hpp b/redfish-core/include/privileges.hpp
index 160816f..f20cede 100644
--- a/redfish-core/include/privileges.hpp
+++ b/redfish-core/include/privileges.hpp
@@ -198,7 +198,8 @@
     }
 
   private:
-    Privileges(const std::bitset<maxPrivilegeCount>& p) : privilegeBitset{p}
+    explicit Privileges(const std::bitset<maxPrivilegeCount>& p) :
+        privilegeBitset{p}
     {}
     std::bitset<maxPrivilegeCount> privilegeBitset = 0;
 };
diff --git a/redfish-core/include/redfish.hpp b/redfish-core/include/redfish.hpp
index c961b2d..8c05dd7 100644
--- a/redfish-core/include/redfish.hpp
+++ b/redfish-core/include/redfish.hpp
@@ -62,7 +62,7 @@
      *
      * @param[in] app   Crow app on which Redfish will initialize
      */
-    RedfishService(App& app)
+    explicit RedfishService(App& app)
     {
         requestAccountServiceRoutes(app);
         requestRoutesRoles(app);
diff --git a/redfish-core/include/server_sent_events.hpp b/redfish-core/include/server_sent_events.hpp
index 6663f66..16d8e18 100644
--- a/redfish-core/include/server_sent_events.hpp
+++ b/redfish-core/include/server_sent_events.hpp
@@ -256,7 +256,8 @@
     ServerSentEvents(ServerSentEvents&&) = delete;
     ServerSentEvents& operator=(ServerSentEvents&&) = delete;
 
-    ServerSentEvents(const std::shared_ptr<boost::beast::tcp_stream>& adaptor) :
+    explicit ServerSentEvents(
+        const std::shared_ptr<boost::beast::tcp_stream>& adaptor) :
         sseConn(adaptor)
     {
         startSSE();