remove is_method_error call

An `is_method_error` is not appropriate after an sdbus `call` since
`call` will always throw an exception.  Remove the pointless call
and instead catch the exception.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ib82c90e78508b5e996ced1d29091dd609f1fba07
diff --git a/user_mgr.cpp b/user_mgr.cpp
index 0029326..efaeb5b 100644
--- a/user_mgr.cpp
+++ b/user_mgr.cpp
@@ -1101,17 +1101,18 @@
     mapperCall.append(std::move(path));
     mapperCall.append(std::vector<std::string>({std::move(intf)}));
 
-    auto mapperResponseMsg = bus.call(mapperCall);
-
-    if (mapperResponseMsg.is_method_error())
+    std::map<std::string, std::vector<std::string>> mapperResponse;
+    try
     {
-        lg2::error("Error in mapper call");
+        auto mapperResponseMsg = bus.call(mapperCall);
+        mapperResponseMsg.read(mapperResponse);
+    }
+    catch (const sdbusplus::exception_t& e)
+    {
+        lg2::error("Error in mapper call: {ERROR}", "ERROR", e.what());
         elog<InternalFailure>();
     }
 
-    std::map<std::string, std::vector<std::string>> mapperResponse;
-    mapperResponseMsg.read(mapperResponse);
-
     if (mapperResponse.begin() == mapperResponse.end())
     {
         lg2::error("Invalid response from mapper");