Fix multiple modules with the same name in FACTORY_RAMDISK_MODULES

With this change, if a module name is associated with multiple modules,
you can specify multiple install paths in
PRODUCT_FACTORY_RAMDISK_MODULES.
For example, if we have 2 modules named "foo", one is Java library and
the other is executable, then you can write:
PRODUCT_FACTORY_RAMDISK_MODULES += \
  foo:system/bin/foo:system/framework/foo.jar
Or:
PRODUCT_FACTORY_RAMDISK_MODULES += \
  foo:system/bin/foo \
  foo:system/framework/foo.jar

The build system will choose the correct built files based on the
install paths.

Change-Id: I6efc72e8abd1e81710ada16731b6792989aefd85