bitbake: toaster: do not fail on optional 'custom.xml' file

Explicitly capture and ignore errors when trying to load the optional
'custom.xml' fixture file.

[YOCTO #12554]

(Bitbake rev: 132458939d3987ebc58685397714af3d6d5cd8fd)

Signed-off-by: David Reyna <David.Reyna@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/toaster/bldcontrol/management/commands/checksettings.py

@@ -107,7 +107,10 @@ class Command(BaseCommand):
                                 action="ignore",
                                 message="^.*No fixture named.*$")
                             print("Importing custom settings if present")
-                            call_command("loaddata", "custom")
+                            try:
+                                call_command("loaddata", "custom")
+                            except:
+                                print("NOTE: optional fixture 'custom' not found")
 
                         # we run lsupdates after config update
                         print("\nFetching information from the layer index, "