beremiz

file isExecutable
fix bug: Beremiz IDE hangs during launching Beremiz_service

this is regression introduced as side effect by d7f474d [fix issue
with sometimes wrong return code of ProcessLogger]
<xsd:attribute name="Command" type="xsd:string" use="optional" default="make -C %(buildpath)s all BEREMIZSRC=%(src)s BEREMIZCFLAGS=%(cflags)s MD5=%(md5)s USE_BEREMIZ=1 FROM_BEREMIZ=1"/>