ECP VELOC Package update (#8910)

* update of veloc & dep versions (replace old non-working versions)

* veloc doesn't work with gcc <= 4.9.3

* explicitly pass MPI to CMake for veloc build

var/spack/repos/builtin/packages/er/package.py

@@ -35,7 +35,7 @@ class Er(CMakePackage):
     tags = ['ecp']
 
     version('master', branch='master')
-    version('0.0.2', '24ad8f87bce2b6d900f1fb67452c3672')
+    version('0.0.3', sha256='9aa08f9fe70e42f0da27a5d90d4643b520d61f24742303bf016322823b3c4d26')
 
     depends_on('mpi')
     depends_on('kvtree')