ash: [PARSER] Do not show prompts in expandstr

ash: [PARSER] Do not show prompts in expandstr

Upstream patch:

    Date: Thu, 27 Dec 2007 13:57:07 +1100
    [PARSER] Do not show prompts in expandstr

    Once I fixed the previous problem it became apparent that we never dealt
    with prompts with new-lines in them correctly.  The problem is that we
    showed a secondary prompt for each of them.

    This patch disables prompt generation in expandstr.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
function                                             old     new   delta
expandstr                                            102     127     +25

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>