qemu-iotests: strip spaces from qemu-img/qemu-io/qemu command lines

A trailing space is left when qemu-img has no arguments, for example if
-nocache is not used.  This becomes an empty argument after split()
and causes qemu-io to fail.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/iotests.py

@@ -28,9 +28,9 @@ __all__ = ['imgfmt', 'imgproto', 'test_dir' 'qemu_img', 'qemu_io',
 
 # This will not work if arguments or path contain spaces but is necessary if we
 # want to support the override options that ./check supports.
-qemu_img_args = os.environ.get('QEMU_IMG', 'qemu-img').split(' ')
-qemu_io_args = os.environ.get('QEMU_IO', 'qemu-io').split(' ')
-qemu_args = os.environ.get('QEMU', 'qemu').split(' ')
+qemu_img_args = os.environ.get('QEMU_IMG', 'qemu-img').strip().split(' ')
+qemu_io_args = os.environ.get('QEMU_IO', 'qemu-io').strip().split(' ')
+qemu_args = os.environ.get('QEMU', 'qemu').strip().split(' ')
 
 imgfmt = os.environ.get('IMGFMT', 'raw')
 imgproto = os.environ.get('IMGPROTO', 'file')