flake8: make entire repository pass spack flake8 -a

- Fix trailing whitespace missed by the bug described in #12755.

- Fix other style issues that have crept in over time (this can happen
  when flake8 adds new checks with new versions)

var/spack/repos/builtin/packages/c-blosc2/package.py

@@ -32,7 +32,7 @@ class CBlosc2(CMakePackage):
             description='support for ZSTD')
 
     depends_on('cmake@2.8.10:', type='build')
-    # TODO https://github.com/inikep/lizard/issues/21 
+    # TODO https://github.com/inikep/lizard/issues/21
     # depends_on('lizard')
     depends_on('lz4')
     depends_on('snappy')