bump to rubygems 1.8.15

.rvmrc

@@ -5,6 +5,6 @@ else
   rvm --create use ree-1.8.7-2011.03@diaspora
 fi
 
-if [ "$(gem --version)" != "1.8.12" ]; then
-  rvm rubygems 1.8.12
+if [ "$(gem --version)" != "1.8.15" ]; then
+  rvm rubygems 1.8.15
 fi

script/ci/before_install.sh

 #!/bin/bash
 
 # Ensure known RubyGems version
-if [ "$(gem --version)" != "1.8.12" ]; then
+if [ "$(gem --version)" != "1.8.15" ]; then
   echo "RubyGems version is $(gem --version). Changing..."
-  rvm rubygems 1.8.12
+  rvm rubygems 1.8.15
   echo "Changed RubyGems version to $(gem --version)."
 fi