libmetrics: linux: reduce buffer size for os release name's slurpfile
libmetrics: linux: reduce buffer size for os release name's slurpfile

value will need to be truncated to a g_string for distribution in
any case so allocating 8192 bytes isn't needed


hinesmr/monitor-core,ganglia/monitor-core,sdgdsffdsfff/monitor-core,fastly/monitor-core,ganglia/monitor-core,NoodlesNZ/monitor-core,torkelsson/monitor-core,mjzhou/monitor-core,mjzhou/monitor-core,NoodlesNZ/monitor-core,NoodlesNZ/monitor-core,NoodlesNZ/monitor-core,lawrencewu/monitor-core,ganglia/monitor-core,hinesmr/monitor-core,NoodlesNZ/monitor-core,dmourati/monitor-core,torkelsson/monitor-core,phreakocious/monitor-core,lawrencewu/monitor-core,sdgdsffdsfff/monitor-core,torkelsson/monitor-core,ganglia/monitor-core,phreakocious/monitor-core,sdgdsffdsfff/monitor-core,dmourati/monitor-core,phreakocious/monitor-core,fastly/monitor-core,hinesmr/monitor-core,lawrencewu/monitor-core,phreakocious/monitor-core,dmourati/monitor-core,dmourati/monitor-core,lawrencewu/monitor-core,ganglia/monitor-core,torkelsson/monitor-core,mjzhou/monitor-core,lawrencewu/monitor-core,torkelsson/monitor-core,dmourati/monitor-core,phreakocious/monitor-core,fastly/monitor-core,sdgdsffdsfff/monitor-core,hinesmr/monitor-core,dmourati/monitor-core,lawrencewu/monitor-core,ganglia/monitor-core,hinesmr/monitor-core,mjzhou/monitor-core,mjzhou/monitor-core,fastly/monitor-core,fastly/monitor-core,sdgdsffdsfff/monitor-core,NoodlesNZ/monitor-core,sdgdsffdsfff/monitor-core,fastly/monitor-core,torkelsson/monitor-core,ganglia/monitor-core,mjzhou/monitor-core,NoodlesNZ/monitor-core,torkelsson/monitor-core,fastly/monitor-core,phreakocious/monitor-core,ganglia/monitor-core,mjzhou/monitor-core,lawrencewu/monitor-core,sdgdsffdsfff/monitor-core,phreakocious/monitor-core