Fix an override_module bug.

proptools.PrependProperties doesn't replace a pointer when both the src
and the dst have one. This prevented override_module from overriding
simple value pointer properties when the base module has existing
values. It turns out this was why the name property needed to be
overwritten manually.

Bug: 122957760
Test: app_test.go
Change-Id: I3302287c31a560422548c22fade95261ddbe606a