search for macros in target dependent paths

When adbd48158b261b replaced macrofiles list to have proper order of
loading, it also hardcoded in it the architecture on which rpm was
build.  Reverse that part of the change so the search paths for macros
depend again on --target argument.
package ix86 macros on ix8664

ix8664 hosts can compile ix86 packages. But to do it correctly
the macros for the given architecture have to be present.