spec: keep spaces in set_var substing

share/eterbuild/functions/spec

@@ -80,7 +80,7 @@ get_txtrelease()
 
 set_var()
 {
-	subst "0,/^$2:/s/^\($2:\).*\$/\1 $3/" $1
+	subst "0,/^$2:/s/^\($2:\)\([[:space:]]*\).*\$/\1\2$3/" $1
 	#subst "s|^\($2:\).*\$|\1 $3|q" $1
 }