[core] Use the error reason phrase if the response body is empty
[core] Use the error reason phrase if the response body is empty

Distrotech/libgdata,pwithnall/libgdata,Pecisk/libgdata,Pecisk/libgdata-gtasks,Pecisk/libgdata-gtasks,Distrotech/libgdata,GNOME/libgdata,pwithnall/libgdata,Pecisk/libgdata,Distrotech/libgdata,Pecisk/libgdata-gtasks,Pecisk/libgdata