Use s.c_str() in log messages

Partly Resolves openbmc/openbmc 2905

Tested: static_assert only

Change-Id: Ic5ca81bd4367d7ca8023bb791b74b938f6f2b68e
Signed-off-by: Joseph Reynolds <jrey@us.ibm.com>
diff --git a/power-supply/power_supply.cpp b/power-supply/power_supply.cpp
index b26c96b..d4c5f74 100644
--- a/power-supply/power_supply.cpp
+++ b/power-supply/power_supply.cpp
@@ -132,8 +132,8 @@
         }
         catch (std::exception& e)
         {
-            log<level::INFO>("Unable to capture metadata", entry("CMD=%s",
-                                                                 cmd));
+            log<level::INFO>("Unable to capture metadata",
+                             entry("CMD=%s", cmd.c_str()));
         }
     }
 }
@@ -769,7 +769,7 @@
     {
         log<level::ERR>(
                 e.what(),
-                entry("PATH=%s", inventoryPath));
+                entry("PATH=%s", inventoryPath.c_str()));
     }
 }