Fix reserving user picked object names.

Bug 19219444

Change-Id: Ic0e3c5a37174917a541452bab9f92738bc766044
Reviewed-on: https://swiftshader-review.googlesource.com/4986
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>