After assembling a band of exploratory roots musicians, Robert Plant used his early-‘10s live shows to push some of his most familiar songs into new shapes. Led Zeppelin favorites “Black Dog” and “Friends” become low-slung funk incantations with tinges of raga, while the fiery strut of “Whole Lotta Love” is transformed into cocksure, steadily rolling grooves. “Somebody Knocking” sets wiry violin curlicues against that doomy blues shuffle, with Plant’s mercurial voice pleading, cajoling, and lamenting like the shamanic bluesman he is.