title: How to inform SBT to consume specific scala version for plugins?
body: <p>Now I somehow messed up my global sbt plugins (<code>~/.sbt/plugins/build.sbt</code>). They were always fine retrieved against Scala 2.9.1 which seems to be the version that sbt 0.11.3 wants, and all the plugins (sbt-gpg-plugin, sbt-idea-plugin) are published against 2.9.1.</p>
  
  <p>Now whatever I do, it persistently tries to find them built against 2.9.2:</p>
  
  <pre><code>[warn]  Note: Some unresolved dependencies have extra attributes.  Check that these dependencies exist with the requested attributes.
  [warn]      com.github.mpeltonen:sbt-idea:1.0.0 (sbtVersion=0.11.3, scalaVersion=2.9.2)
  [warn]      com.jsuereth:xsbt-gpg-plugin:0.6 (sbtVersion=0.11.3, scalaVersion=2.9.2)
  ...
  [error] {file:...}default-50be6e/*:update: sbt.ResolveException: unresolved dependency: com.github.mpeltonen#sbt-idea;1.0.0: not found
  </code></pre>
  
  <p>How can I fix this, so sbt retrieves the plugins for Scala 2.9.1 as before?</p>
  
  <hr>
  
  <p>For the sake of completeness, this is how my files look after the suggestions:</p>
  
  <pre><code>// project-home/build.sbt
  scalaVersion := "2.9.2"
  ...
  </code></pre>
  
  <p> </p>
  
  <pre><code>// project-home/project/plugins.sbt
  resolvers += "less is" at "http://repo.lessis.me"
  
  addSbtPlugin( "me.lessis" % "ls-sbt" % "0.1.1" )
  
  scalaVersion := "2.9.1"  // "just in case it helps"
  </code></pre>
  
  <p> </p>
  
  <pre><code>// ~/.sbt/plugins/build.sbt
  scalaVersion := "2.9.1"  // "just in case it helps"
  
  resolvers += "sbt-idea-repo" at "http://mpeltonen.github.com/maven/"
  
  resolvers += Resolver.url( "sbt-plugin-releases", url( "http://scalasbt.artifactoryonline.com/scalasbt/sbt-plugin-releases" ))( Resolver.ivyStylePatterns )
  
  addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.0.0")
  
  addSbtPlugin( "com.jsuereth" % "xsbt-gpg-plugin" % "0.6" )
  </code></pre>
  
  <hr>
  
  <p>What is even worse, the problem persists, even after I <strong>removed</strong> <code>~/.sbt/plugins/build.sbt</code>. So there are no more references (at least visible to me) to either sbt-idea or xsbt-gpg-plugin. Still I cannot compile any project any more, because sbt still tries to find those two plugins. Epic fail.</p>