Convert the command in tuple to string when calling Popen to launch external command. This is to make sure of no failure when launching a tool with more than one switches.
Convert the command in tuple to string when calling Popen to launch external command. This is to make sure of no failure when launching a tool with more than one switches.

git-svn-id: f3880c1fc5096ce2109c8aec392d8e07f619f417@1413 c2973edb-eda0-4c78-bc6a-9341b269661f

tianocore/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,tianocore/buildtools-BaseTools,tianocore/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,tianocore/buildtools-BaseTools,tianocore/buildtools-BaseTools