Change libjson to libjsoncpp in .gitignore

.gitignore

@@ -4,6 +4,8 @@
 *bak*
 tags
 *.vim
+*.orig
+*.rej
 
 ## Non-static Minetest directories
 /bin/
@@ -41,7 +43,7 @@ src/cguittfont/libcguittfont.a
 src/cguittfont/cmake_install.cmake
 src/cguittfont/Makefile
 src/json/CMakeFiles/
-src/json/libjson.a
+src/json/libjsoncpp.a
 CMakeCache.txt
 CPackConfig.cmake
 CPackSourceConfig.cmake