Remove unused DECnet code
Remove unused DECnet code

"unifdef -UDNETCONN src/xcb_util.c" plus re-indenting code that was
formerly in the else clause after a DECnet check.

DECnet support has been removed from most of the X.Org code base for
several years, and it appears DNETCONN was never defined in XCB.

Signed-off-by: Alan Coopersmith <ea3248f8c2440b9439894eab21ef26209b22bacf@oracle.com>
Reviewed-by: Jamey Sharp <167c1dcbbc9c320e8e02a0c15c886204b4e658a4@minilop.net>

stapelberg/libxcb,stapelberg/libxcb,stapelberg/libxcb