Add 'blockdev' output for all mount points with leading slash

From a recent Tweet of mine:

    # blockdev --getra /dev/md2
      327680

    160MByte read-ahead at the block device level? Really? REALLY??  #INCOHERENTRAGE
Add cluster-info output to Riak commands list
Review: Add 'local' to cluster-info invocation
Merge pull request #456 from basho/slf-riak-debug-additions

Riak debug additions