mouse: Don't enable two-finger scrolling based on width

Reverts part of 109b369199

Good idea in principle, albeit the hardware gets in our way. In
synaptics 1.4 two-finger emulation was enabled by default on devices
that reported finger width but had to since revert this. The hardware
doesn't really separate width and pressure, so a hard tap off a finger
gives a high width, a wide finger gives a high pressure on light
touches. We got spurious right-click presses when two-finger
emulation was enabled.

Now we have the control-center providing a checkbox for two-finger
emulation but it doesn't enable emulation, which to the users appears as if
two-finger scrolling is broken
(https://bugzilla.redhat.com/show_bug.cgi?id=738123).

We now disable the checkbox again for hardware that doesn't do two-fingers.
it's not reliable and we're likely to see further bugs when the spurious right
clicks take effect

https://bugzilla.gnome.org/show_bug.cgi?id=661963

panels/mouse/gnome-mouse-properties.c

@@ -234,8 +234,8 @@ synaptics_check_capabilities (GtkBuilder *dialog)
 			}
 
 			/* Disable two finger scrolling unless the hardware supports
-			 * double touch or can emulate it based on finger width. */
-			if (!(data[3] ||(nitems >= 6 && data[5])))
+			 * double touch */
+			if (!(data[3]))
 				gtk_widget_set_sensitive (WID ("scroll_twofinger_radio"), FALSE);
 
 			XFree (data);