[petsc-dev] plex error in master

[Barry Smith]

---- WARNINGS ----
/sandbox/petsc/petsc.clone-2/src/dm/impls/plex/plexsubmesh.c:1575:17: warning: 
absolute value function 'abs' given an argument of type 'PetscInt' (aka 'long') 
but has parameter of type 'int' which may cause truncation of value 
[-Wabsolute-value]
1 warning generated.