Merge pull request #156 from sbt/wip/rpm-spec-buildarch

FIX #112 Adding BuildArch to the spec file

Author: jsuereth

src/main/scala/com/typesafe/sbt/packager/rpm/RpmMetadata.scala

@@ -189,7 +189,8 @@ case class RpmSpec(meta: RpmMetadata,
     sb append ("autoprov: %s\n" format meta.autoprov)
     sb append ("autoreq: %s\n" format meta.autoreq)
 
-    sb append ("BuildRoot: %s\n\n" format rpmRoot.getAbsolutePath)
+    sb append ("BuildRoot: %s\n" format rpmRoot.getAbsolutePath)
+    sb append ("BuildArch: %s\n\n" format meta.arch)
 
     sb append "%description\n"
     sb append meta.description