perl: improved perl.conf to set vendorprefix and removed superfluous whitespace.

We lost the ability to set vendorprefix at 23f83f9dc35c4ece3fd710c18cfd5a63babdf3fc,
we need it because http://git.opensde.net/opensde/opensde-nopast/commit/?id=aabb0ba8327333231997f77910673fefda46935c

perl/perl/perl.conf

@@ -26,12 +26,13 @@ extraconfopt=
 makeinstopt="install"
 
 if ! atstage native; then
-	var_append extraconfopt ' ' "--target=$arch_target" 
+	var_append extraconfopt ' ' "--target=$arch_target"
 	var_insert makeinstopt ' ' "DESTDIR=$root"
 fi
 
 # let -D and -U override definitions from loaded configuration file
 var_append extraconfopt ' ' "-O"
+var_append extraconfopt ' ' "-Dusevendorprefix"
 
 # build a shared libperl
 if [ "$SDECFG_STATIC" != 1 ]; then