Fix permissions back to 0644

[strzibny]

Hi, I noticed that some files changed permissions and are now executable:

$ gem compare rack-protection 1.2.0 1.5.0 -kb
Fetching: rack-protection-1.2.0.gem (100%)
Compared versions: ["1.2.0", "1.5.0"]
  DIFFERENT authors:
    1.2.0: ["Konstantin Haase", "Akzhan Abdulin", "Corey Ward", "David Kellum", "Fojas", "Martin Mauch"]
    1.5.0: ["Konstantin Haase", "Alex Rodionov", "Chris Heald", "Chris Mytton", "Corey Ward", "David Kellum", "Egor Homakov", "Florian Gilcher", "Fojas", "Mael Clerambault", "Martin Mauch", "SAKAI, Kazuaki", "Stanislav Savulchik", "Steve Agalloco", "Akzhan Abdulin", "TOBY", "Bjørge Næss"]
  DIFFERENT email:
    1.2.0: ["konstantin.mailinglists@googlemail.com", "akzhan.abdulin@gmail.com", "coreyward@me.com", "dek-oss@gravitext.com", "developer@fojasaur.us", "martin.mauch@gmail.com"]
    1.5.0: ["konstantin.mailinglists@googlemail.com", "p0deje@gmail.com", "self@hecticjeff.net", "coreyward@me.com", "dek-oss@gravitext.com", "homakov@gmail.com", "florian.gilcher@asquera.de", "developer@fojasaur.us", "mael@clerambault.fr", "martin.mauch@gmail.com", "kaz.july.7@gmail.com", "s.savulchik@gmail.com", "steve.agalloco@gmail.com", "akzhan.abdulin@gmail.com", "toby.net.info.mail+git@gmail.com", "bjoerge@bengler.no", "cheald@gmail.com"]
  DIFFERENT files:
    1.2.0->1.5.0:
      * Changed:
            lib/rack/protection/base.rb +16/-1
              (!) New permissions: 100644 -> 100755
              (!) File is now executable!
            spec/protection_spec.rb +29/-0
              (!) New permissions: 100644 -> 100755
              (!) File is now executable!

This PR changes the perms back.

[rkh]

Thank you! :)