Enable readability-container-size-empty tests

This one is a little trivial, but it does help in readability.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I5366d4eec8af2f781b3bad804131ae2eb806e3aa
diff --git a/redfish-core/lib/certificate_service.hpp b/redfish-core/lib/certificate_service.hpp
index fa9cc2f..34f6770 100644
--- a/redfish-core/lib/certificate_service.hpp
+++ b/redfish-core/lib/certificate_service.hpp
@@ -293,7 +293,7 @@
             // password, which will likely cause bmcweb to crash on startup
             // if this is not set on a post so not allowing the user to set
             // value
-            if (*optChallengePassword != "")
+            if (!optChallengePassword->empty())
             {
                 messages::actionParameterNotSupported(
                     asyncResp->res, "GenerateCSR", "ChallengePassword");
@@ -355,7 +355,7 @@
                     certURI,
                     "/redfish/v1/Managers/bmc/NetworkProtocol/HTTPS/Certificates"))
             {
-                if (optKeyUsage->size() == 0)
+                if (optKeyUsage->empty())
                 {
                     optKeyUsage->push_back("ServerAuthentication");
                 }
@@ -379,7 +379,7 @@
                          certURI,
                          "/redfish/v1/AccountService/LDAP/Certificates"))
             {
-                if (optKeyUsage->size() == 0)
+                if (optKeyUsage->empty())
                 {
                     optKeyUsage->push_back("ClientAuthentication");
                 }