beremiz

file isExecutable
fix non-working logging at first connection to PLC after Beremiz launch

At the same time this helps to avoid exception described in 1484:d5efbb20927e.
<xsd:attribute name="Compiler" type="xsd:string" use="optional" default="gcc"/>
<xsd:attribute name="CFLAGS" type="xsd:string" use="optional" default=""/>
<xsd:attribute name="Linker" type="xsd:string" use="optional" default="gcc"/>
<xsd:attribute name="LDFLAGS" type="xsd:string" use="optional" default=""/>