installer.sh.in: add -f flag to mkfs.f2fs

Without -f, mkfs.f2fs refuses to overwrite an existing filesystem, causing installation to fail. With this flag we match the behavior of the other filesystems.

installer.sh.in

@@ -1031,7 +1031,7 @@ failed to activate swap on $dev!\ncheck $LOG for errors." ${MSGBOXSIZE}
             ext2) MKFS="mke2fs -F"; modprobe ext2 >$LOG 2>&1;;
             ext3) MKFS="mke2fs -F -j"; modprobe ext3 >$LOG 2>&1;;
             ext4) MKFS="mke2fs -F -t ext4"; modprobe ext4 >$LOG 2>&1;;
-            f2fs) MKFS="mkfs.f2fs"; modprobe f2fs >$LOG 2>&1;;
+            f2fs) MKFS="mkfs.f2fs -f"; modprobe f2fs >$LOG 2>&1;;
             vfat) MKFS="mkfs.vfat -F32"; modprobe vfat >$LOG 2>&1;;
             xfs) MKFS="mkfs.xfs -f -i sparse=0"; modprobe xfs >$LOG 2>&1;;
             esac