qemu-iotests: Add missing -machine accel=qtest

A basic set of qemu options is initialised in ./common:

    export QEMU_OPTIONS="-nodefaults -machine accel=qtest"

However, two test cases (172 and 186) overwrite QEMU_OPTIONS and neglect
to manually set '-machine accel=qtest'. Add the missing option for 172.
186 probably only copied the code from 172, it doesn't actually need to
overwrite QEMU_OPTIONS, so remove that in 186.

Signed-off-by: Kevin Wolf <[email protected]>
Tested-by: Cornelia Huck <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>

tests/qemu-iotests/172

@@ -56,7 +56,7 @@ function do_run_qemu()
             done
         fi
         echo quit
-    ) | $QEMU -nographic -monitor stdio -serial none "$@"
+    ) | $QEMU -machine accel=qtest -nographic -monitor stdio -serial none "$@"
     echo
 }
 

tests/qemu-iotests/186

@@ -56,15 +56,15 @@ function do_run_qemu()
             done
         fi
         echo quit
-    ) | $QEMU -S -nodefaults -display none -device virtio-scsi-pci -monitor stdio "$@" 2>&1
+    ) | $QEMU -S -display none -device virtio-scsi-pci -monitor stdio "$@" 2>&1
     echo
 }
 
 function check_info_block()
 {
     echo "info block" |
-    QEMU_OPTIONS="" do_run_qemu "$@" | _filter_win32 | _filter_hmp |
-        _filter_qemu | _filter_generated_node_ids
+    do_run_qemu "$@" | _filter_win32 | _filter_hmp | _filter_qemu |
+        _filter_generated_node_ids
 }