Use s.c_str() in log messages

Fixes issues with data passed to phosphor::logging::log(entry()).
This is part of a series of commits that resolves openbmc 2905.

Tested: static_assert only

Change-Id: I9fac771f54e4acbec97ce1360c106b6e3eb4fe9d
Signed-off-by: Joseph Reynolds <jrey@us.ibm.com>
diff --git a/sensordatahandler.cpp b/sensordatahandler.cpp
index 20006dc..2d4ac3a 100644
--- a/sensordatahandler.cpp
+++ b/sensordatahandler.cpp
@@ -44,8 +44,8 @@
     if (mapperResponseMsg.is_method_error())
     {
         log<level::ERR>("Mapper GetSubTree failed",
-                        entry("PATH=%s", path),
-                        entry("INTERFACE=%s", interface));
+                        entry("PATH=%s", path.c_str()),
+                        entry("INTERFACE=%s", interface.c_str()));
         elog<InternalFailure>();
     }
 
@@ -54,8 +54,8 @@
     if (mapperResponse.empty())
     {
         log<level::ERR>("Invalid mapper response",
-                        entry("PATH=%s", path),
-                        entry("INTERFACE=%s", interface));
+                        entry("PATH=%s", path.c_str()),
+                        entry("INTERFACE=%s", interface.c_str()));
         elog<InternalFailure>();
     }
 
@@ -69,8 +69,8 @@
     if (iter == mapperResponse.end())
     {
         log<level::ERR>("Couldn't find D-Bus path",
-                        entry("PATH=%s", path),
-                        entry("INTERFACE=%s", interface));
+                        entry("PATH=%s", path.c_str()),
+                        entry("INTERFACE=%s", interface.c_str()));
         elog<InternalFailure>();
     }
     return std::make_pair(iter->first, iter->second.begin()->first);