client: fix adding to playlist using incorrect sort key
client: fix adding to playlist using incorrect sort key

See #33

dwrensha/groovebasin,andrewrk/groovebasin,emersion/groovebasin,andrewrk/groovebasin,emersion/groovebasin,melissanoelle/groovebasin,gorlug/groovebasin,sammcj/groovebasin,neynah/groovebasin,neynah/groovebasin,gorlug/groovebasin,sammcj/groovebasin,CalebMorris/groovebasin,CalebMorris/groovebasin,melissanoelle/groovebasin,melissanoelle/groovebasin,neynah/groovebasin,andrewrk/groovebasin,CalebMorris/groovebasin,Qbuer/groovebasin,gorlug/groovebasin,dwrensha/groovebasin,dwrensha/groovebasin,emersion/groovebasin,Qbuer/groovebasin,dwrensha/groovebasin,sammcj/groovebasin,Qbuer/groovebasin