[GNOME-my]Test/improve em-junk-filter patch for evo 1.5.1

[Khairil Yusof <kaeru pd jaring my>]

both bin sh and bash have a problem with Evo 1.5.1's command line
argument for calling spamassassin.

/bin/sh -c sa-learn --local --norebuild (and similar)

These will fail silently, because sh get's confused by --, so you need
to quote the command string

/bin/sh -c 'sa-learn --local --norebuild'

Then it will work properly. I did a quick hack to fix this, it compiles
ok, but not tested yet. I'm not a C programmer, but I see that simply
adding quotes is rather simplistic fix. ;)

I'm going to submit the patch later, for anybody testing 1.5.1, please
try compiling it and testing this patch.

Thanks.