docker: exec $CMD

This is the last command to run (unless DEBUG), make it 'exec' to
simplify the process tree.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-Id: <1474429768-25027-10-git-send-email-famz@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>

tests/docker/run

@@ -57,14 +57,17 @@ cd "$QEMU_SRC/tests/docker"
 
 CMD="$QEMU_SRC/tests/docker/$@"
 
-if test -n "$DEBUG"; then
-    echo "* Prepared to run command:"
-    echo "  $CMD"
-    echo "* Hit Ctrl-D to continue, or type 'exit 1' to abort"
-    echo
-    $SHELL
+if test -z "$DEBUG"; then
+    exec $CMD
 fi
 
+# DEBUG workflow
+echo "* Prepared to run command:"
+echo "  $CMD"
+echo "* Hit Ctrl-D to continue, or type 'exit 1' to abort"
+echo
+$SHELL
+
 if "$CMD"; then
     exit 0
 elif test -n "$DEBUG"; then