Fix compilation error (hope)

vendor/tmobile/apps/ThemeChooser/src/com/tmobile/themechooser/ThemeChooser.java:345: cannot find symbol
symbol  : method getPreviewHash()
location: class com.tmobile.themes.provider.ThemeItem
            String hash = themeItem.getPreviewHash();
                                   ^
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
1 error
make: *** [/home/marco/repo/aokp/out/target/common/obj/APPS/ThemeChooser_intermediates/classes-full-debug.jar] Error 41
make: *** Waiting for unfinished jobs....