qt4: fix seek support in VLM
qt4: fix seek support in VLM

clang was giving a warning about the addition of a const char* with an integer.

jomanmuk/vlc-2.2,krichter722/vlc,xkfz007/vlc,shyamalschandra/vlc,shyamalschandra/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,xkfz007/vlc,shyamalschandra/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,shyamalschandra/vlc,krichter722/vlc,xkfz007/vlc,krichter722/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,shyamalschandra/vlc,vlc-mirror/vlc,vlc-mirror/vlc,vlc-mirror/vlc,krichter722/vlc,xkfz007/vlc,vlc-mirror/vlc,vlc-mirror/vlc,krichter722/vlc,jomanmuk/vlc-2.2,krichter722/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,xkfz007/vlc,krichter722/vlc