CA Cert: Fix D-bus object path

Modify object path as static const char

Signed-off-by: Ravi Teja <raviteja28031990@gmail.com>
Change-Id: I49cbd086dca38f30b103a5a3077f613c50c8520b
diff --git a/bmc-vmi-ca/mainapp.cpp b/bmc-vmi-ca/mainapp.cpp
index 8c1aa06..28b05bc 100644
--- a/bmc-vmi-ca/mainapp.cpp
+++ b/bmc-vmi-ca/mainapp.cpp
@@ -8,10 +8,10 @@
 int main(int argc, char** argv)
 {
     auto bus = sdbusplus::bus::new_default();
-    std::string objPath = "/xyz/openbmc_project/certs/ca";
+    static constexpr auto objPath = "/xyz/openbmc_project/certs/ca";
 
     // Add sdbusplus ObjectManager
-    sdbusplus::server::manager::manager objManager(bus, objPath.c_str());
+    sdbusplus::server::manager::manager objManager(bus, objPath);
 
     // Get default event loop
     auto event = sdeventplus::Event::get_default();
@@ -19,7 +19,7 @@
     // Attach the bus to sd_event to service user requests
     bus.attach_event(event.get(), SD_EVENT_PRIORITY_NORMAL);
 
-    ca::cert::CACertMgr manager(bus, event, objPath.c_str());
+    ca::cert::CACertMgr manager(bus, event, objPath);
 
     std::string busName = "xyz.openbmc_project.Certs.ca.authority.Manager";
     bus.request_name(busName.c_str());