grub2: add missing SECTION variable and remove non breaking space

Fix metadata scan failure in the grub2 package by removing an unexpected
invisible space character and by adding back the missing SECTION variable
which was removed with d140648.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/boot/grub2/Makefile

@@ -28,7 +28,8 @@ include $(INCLUDE_DIR)/host-build.mk
 include $(INCLUDE_DIR)/package.mk
 
 define Package/grub2
-  CATEGORY:=Boot Loaders
+  CATEGORY:=Boot Loaders
+  SECTION:=boot
   TITLE:=GRand Unified Bootloader
   URL:=http://www.gnu.org/software/grub/
   DEPENDS:=@TARGET_x86||TARGET_x86_64