some config.* files were not ignored due to trailing white space

removed duplicate entries while at it

[[Imported from SVN: r1925]]

.gitignore

 Makefile
 Makefile.in
-config.guess  
-config.h.in   
-config.log  
+config.guess
+config.h.in
+config.log
 config.status
-config.h      
-config.lt   
+config.h
+config.lt
 config.sub
 configure
 dependencies.m4
@@ -25,5 +25,3 @@ dune-istl-?.?
 ltmain.sh
 am
 .libs
-config.guess
-config.h.in