test: fix check in test unit in TEST-50-DISSECT

'[[ not found'

diff --git a/test/units/testsuite-50.sh b/test/units/testsuite-50.sh
index 44889779ccb2810bee4b125736884ec98c45d2f3..7bede7da1ab8f3e769c4b640679edea8689ce723 100755 (executable)
--- a/test/units/testsuite-50.sh
+++ b/test/units/testsuite-50.sh
@@ -351,7 +351,7 @@ MountAPIVFS=yes
 PrivateTmp=yes
 ExecStart=/bin/sh -c ' \\
     systemd-notify --ready; \\
-    while [[ ! -f /tmp/img/usr/lib/os-release ]] || ! grep -q -F MARKER /tmp/img/usr/lib/os-release; do \\
+    while [ ! -f /tmp/img/usr/lib/os-release ] || ! grep -q -F MARKER /tmp/img/usr/lib/os-release; do \\
         sleep 0.1; \\
     done; \\
     mount; \\