test(e2e): replace process substitution with pipe in two-volume-rd

Process substitution `<(...)` failed in the satellite container with
'/dev/fd/63: No such file or directory' — the debian-slim image's
shell can't see /proc/self/fd in this exec context. Switch to a
plain pipe (dd ... | md5sum | awk).

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Andrei Kvapil <kvapss@gmail.com>

Author: kvaps

tests/e2e/two-volume-rd.sh

@@ -71,11 +71,11 @@ on_node "$N1" drbdadm primary "$RD" 2>/dev/null || true
 
 md5_v0=$(on_node "$N1" bash -c "
     dd if=/dev/urandom of=${DEV0} bs=4096 count=1 status=none oflag=direct
-    md5sum < <(dd if=${DEV0} bs=4096 count=1 status=none iflag=direct) | awk '{print \$1}'
+    dd if=${DEV0} bs=4096 count=1 status=none iflag=direct | md5sum | awk '{print \$1}'
 ")
 md5_v1=$(on_node "$N1" bash -c "
     dd if=/dev/urandom of=${DEV1} bs=4096 count=1 status=none oflag=direct
-    md5sum < <(dd if=${DEV1} bs=4096 count=1 status=none iflag=direct) | awk '{print \$1}'
+    dd if=${DEV1} bs=4096 count=1 status=none iflag=direct | md5sum | awk '{print \$1}'
 ")
 on_node "$N1" drbdadm secondary "$RD" || true
 
@@ -86,8 +86,8 @@ fi
 
 # Replica side: both volumes must read identical data after a peer flip.
 on_node "$N2" drbdadm primary "$RD"
-md5_v0_peer=$(on_node "$N2" bash -c "md5sum < <(dd if=${DEV0} bs=4096 count=1 status=none iflag=direct) | awk '{print \$1}'")
-md5_v1_peer=$(on_node "$N2" bash -c "md5sum < <(dd if=${DEV1} bs=4096 count=1 status=none iflag=direct) | awk '{print \$1}'")
+md5_v0_peer=$(on_node "$N2" bash -c "dd if=${DEV0} bs=4096 count=1 status=none iflag=direct | md5sum | awk '{print \$1}'")
+md5_v1_peer=$(on_node "$N2" bash -c "dd if=${DEV1} bs=4096 count=1 status=none iflag=direct | md5sum | awk '{print \$1}'")
 on_node "$N2" drbdadm secondary "$RD"
 
 if [[ "$md5_v0" != "$md5_v0_peer" ]]; then