title: unable to resign apk in Calabash Android
body: <p>I want to set up calabash android for APK testing from my Windows 7 machine. I have installed <code>Android Studio</code>, <code>Ruby</code> and JA<code>enter code here</code>VA <code>JDK</code>. i have also setup the environment variable properly. below is the version of </p>
  
  <pre><code>    C:\Users\username&gt;ruby -v
       ruby 2.4.2p198 (2017-09-14 revision 59899) [x64-mingw32]
  
      C:\Users\username&gt;gem -v
       2.6.13
  
      C:\Users\username&gt;java -version
       java version "9.0.1"
       Java(TM) SE Runtime Environment (build 9.0.1+11)
       Java HotSpot(TM) 64-Bit Server VM (build 9.0.1+11, mixed mode)
  </code></pre>
  
  <p>I have generated the key store and calabash setup done successfully. But during resign the apk i am getting below error.</p>
  
  <pre><code>C:\calabash-test-android\Automation&gt;bundle exec calabash-android resign 
  C:\calabash-test-android\Automation\UAT-release.apk
  C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/calabash-android-0.9.0/lib/calabash-
  android/java_keystore.rb:60:in `sign_apk': Could not sign app: 
  C:/Users/TEST~1.SAD/AppData/Local/Temp/d20171204-8720-1yhtd9r/unsigned.apk 
   (RuntimeError)
      from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/calabash-android-0.9.0/lib/c
     alabash-android/helpers.rb:164:in `sign_apk'
      from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/calabash-android-0.9.0/lib/c
   alabash-android/helpers.rb:119:in `block in resign_apk'
      from C:/Ruby24-x64/lib/ruby/2.4.0/tmpdir.rb:89:in `mktmpdir'
      from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/calabash-android-0.9.0/lib/c
   alabash-android/helpers.rb:113:in `resign_apk'
      from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/calabash-android-0.9.0/bin/c
   alabash-android:133:in `&lt;top (required)&gt;'
      from C:/Ruby24-x64/bin/calabash-android:23:in `load'
      from C:/Ruby24-x64/bin/calabash-android:23:in `&lt;main&gt;'
  </code></pre>