btrfs-progs: tests: fix misc/016 encoded write, permissions of send stream file

To be able to run the test suite on NFS the temporary files need to be
writeable for all, root due to send and owner due to the way it's
created.

Signed-off-by: David Sterba <dsterba@suse.com>

tests/misc-tests/053-receive-write-encoded/test.sh

@@ -22,7 +22,7 @@ send_one() {
 
 	algorithm="$1"
 	shift
-	str="$1"
+	file="$1"
 	shift
 
 	subv="subv-$algorithm"
@@ -31,11 +31,14 @@ send_one() {
 	run_check_mount_test_dev "-o" "compress-force=$algorithm"
 	cd "$TEST_MNT" || _fail "cannot chdir to TEST_MNT"
 
+	trucate -s0 "$file"
+	chmod a+w "$file"
+
 	run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$subv"
 	run_check $SUDO_HELPER dd if=/dev/zero of="$subv/file1" bs=1M count=1
 	run_check $SUDO_HELPER dd if=/dev/zero of="$subv/file2" bs=500K count=1
 	run_check $SUDO_HELPER "$TOP/btrfs" subvolume snapshot -r "$subv" "$snap"
-	run_check $SUDO_HELPER "$TOP/btrfs" send -f "$str" "$snap" "$@"
+	run_check $SUDO_HELPER "$TOP/btrfs" send -f "$file" "$snap" "$@"
 
 	cd "$here" || _fail "cannot chdir back to test directory"
 	run_check_umount_test_dev
@@ -43,6 +46,7 @@ send_one() {
 
 receive_one() {
 	local str
+
 	str="$1"
 	shift
 
@@ -56,6 +60,7 @@ receive_one() {
 test_one_write_encoded() {
 	local str
 	local algorithm
+
 	algorithm="$1"
 	shift
 	str="$here/stream-$algorithm.stream"
@@ -68,6 +73,7 @@ test_one_write_encoded() {
 test_one_stream_v1() {
 	local str
 	local algorithm
+
 	algorithm="$1"
 	shift
 	str="$here/stream-$algorithm.stream"
@@ -81,6 +87,7 @@ test_mix_write_encoded() {
 	local strzlib
 	local strlzo
 	local strzstd
+
 	strzlib="$here/stream-zlib.stream"
 	strlzo="$here/stream-lzo.stream"
 	strzstd="$here/stream-zstd.stream"