btrfs-progs: fix check for btrfs in btrfs scan

The previous implementation always succeeded so no scan was performed.
This now fixes that and it correctly scans for BTRFS  devices if BTRFS
support is in kernel.

Signed-off-by: Karel Kočí <karel.koci@nic.cz>

utils/btrfs-progs/Makefile

@@ -7,7 +7,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=btrfs-progs
 PKG_VERSION:=5.4.1
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-v$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/linux/kernel/people/kdave/btrfs-progs

utils/btrfs-progs/files/btrfs-scan.init

@@ -1,7 +1,9 @@
 #!/bin/sh
 
 preinit_btrfs_scan() {
-	grep -vq btrfs /proc/filesystems || btrfs device scan
+	if grep -q btrfs /proc/filesystems; then
+		 btrfs device scan
+	fi
 }
 
 boot_hook_add preinit_main preinit_btrfs_scan