component/phantomjs: use buildout conditional sections

multiarch() is being removed from slapos.recipe.build , it was not
needed because we can achieve this with buildout conditional sections as
we did here.

component/phantomjs/buildout.cfg

@@ -10,13 +10,11 @@ recipe = slapos.recipe.build
 slapos_promise =
   file:phantomjs-slapos
 
-base = https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-1.9.7-linux
-i386-linux-gnu   = ${:base}-i686.tar.bz2   9c1426eef5b04679d65198b1bdd6ef88
-x86_64-linux-gnu = ${:base}-x86_64.tar.bz2 f278996c3edd0e8d8ec4893807f27d71
+url = https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-1.9.7-linux${:url-extension}
 
 install =
   import os
-  extract_dir = self.extract(self.download(*options[multiarch()].split()))
+  extract_dir = self.extract(self.download(options['url'], options['md5sum']))
   workdir = guessworkdir(extract_dir)
   self.copyTree(workdir, location)
   with open(os.path.join(location, "phantomjs-slapos"), 'w') as wrapper:
@@ -27,3 +25,11 @@ install =
   exec %(location)s/bin/phantomjs "$@"
   """ % options)
     os.fchmod(wrapper.fileno(), 0o755)
+
+[phantomjs:bits32]
+url-extension = -i686.tar.bz2
+md5sum = 9c1426eef5b04679d65198b1bdd6ef88
+
+[phantomjs:bits64]
+url-extension = -x86_64.tar.bz2 
+md5sum = f278996c3edd0e8d8ec4893807f27d71