flake8 fixes

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

@@ -27,6 +27,7 @@
 # Only build certain parts of dwarf because the other ones break.
 dwarf_dirs = ['libdwarf', 'dwarfdump2']
 
+
 class Libdwarf(Package):
     """The DWARF Debugging Information Format is of interest to
        programmers working on compilers and debuggers (and any one
@@ -51,7 +52,6 @@ class Libdwarf(Package):
 
     parallel = False
 
-
     def install(self, spec, prefix):
         # dwarf build does not set arguments for ar properly
         make.add_default_arg('ARFLAGS=rcs')