Remove a problematic remnant of singlePV.

commit bfded4f79313c047076a5ba5d2c29f7380c270d5 removed only part of
a conditional clause that should have been removed completely. The result
was that all actions that create LVs within a given VG required each
other, leading to cycles in the tsort input graph.

(cherry picked from commit b7df9214bfc35dba0e3a7b5c6251d0e50b10f442)
Resolves: rhbz#1147985