update rails and its dependencies including i18n and nokogiri

for fixing these security issues:

CVE-2013-6415
CVE-2013-4491
CVE-2013-6417
CVE-2013-6416
CVE-2013-4492
CVE-2013-6460
CVE-2013-6461
CVE-2014-0081
CVE-2014-0080
CVE-2013-6414
fix sunspot:solr: constraint version and fix travis configuration

updating sunspot:solr to the latest version was giving errors, thus I
constraint the version in the Gemfile so that it only does minor updates
Merge pull request #66 from SUSE/review_140411_update_rails_i18n_nokogiri

update rails and its dependencies including i18n and nokogiri