Rename all error_code instances to ec

We're not consistent here, which leads to people copying and pasting
code all over, which has lead to a bunch of different names for error
codes.

This commit changes to coerce them all to "ec", because that's what
boost uses for a naming convention.

Tested: Rename only, code compiles.

Change-Id: I7053cc738faa9f7a82f55fc46fc78618bdf702a5
Signed-off-by: Ed Tanous <edtanous@google.com>
diff --git a/redfish-core/lib/power.hpp b/redfish-core/lib/power.hpp
index 4aaac67..f9063b7 100644
--- a/redfish-core/lib/power.hpp
+++ b/redfish-core/lib/power.hpp
@@ -144,12 +144,12 @@
 
         using Mapper = dbus::utility::MapperGetSubTreePathsResponse;
         auto chassisHandler =
-            [sensorAsyncResp](const boost::system::error_code& e,
+            [sensorAsyncResp](const boost::system::error_code& ec2,
                               const Mapper& chassisPaths) {
-            if (e)
+            if (ec2)
             {
                 BMCWEB_LOG_ERROR
-                    << "Power Limit GetSubTreePaths handler Dbus error " << e;
+                    << "Power Limit GetSubTreePaths handler Dbus error " << ec2;
                 return;
             }