PackageNamePermissionQuery uid->userId

PackageNamePermissionQuery (and all that uses it) speaks
of uid, but it actually stores/queries a userId. We therefore
rename the variable/parameter from uid to userId, as appropriate.

Bug: 163651060
Test: still compiles (no functional changes were made)
Change-Id: I3db2263a3f960d7eda35466a2e9058fe6f27e49a