Use universal rubygems method for installing gems

The current implementation for installing gems via `rake spec:deps`
builds a rubygems command that includes all of the gems in a single
oneliner with gem names and versions that are colon delimited:

    $ ruby -S gem install --no-ri --no-rdoc --conservative 'automatiek:~> 1.0.0' 'mustache:0.99.6' ...

This functionality does not exist prior to rubygems 2.0, so this will
not function with the rubygems that ships with ruby 1.9.3

Splitting this into individual `ruby -S gem install` calls for rubygems
versions prior to 2.0, and using the `-v` flag allows this to function
on older implemetations.

1 files changed, 11 insertions, 4 deletions

diff --git a/Rakefile b/Rakefile
index 6f08086731..ff73441bd4 100644
--- a/Rakefile
+++ b/Rakefile
@@ -47,10 +47,17 @@ namespace :spec do
       deps.delete("rdiscount")
     end
 
-    gem_install_command = "install --no-ri --no-rdoc --conservative " + deps.sort_by {|name, _| name }.map do |name, version|
-      "'#{name}:#{version}'"
-    end.join(" ")
-    sh %(#{Gem.ruby} -S gem #{gem_install_command})
+    if Gem::VERSION < "2.0.0"
+      deps.sort_by {|name, _| name }.map do |name, version|
+        gem_install_command = "install --no-ri --no-rdoc --conservative #{name} -v '#{version}'"
+        sh %(#{Gem.ruby} -S gem #{gem_install_command})
+      end
+    else
+      gem_install_command = "install --no-ri --no-rdoc --conservative " + deps.sort_by {|name, _| name }.map do |name, version|
+        "'#{name}:#{version}'"
+      end.join(" ")
+      sh %(#{Gem.ruby} -S gem #{gem_install_command})
+    end
 
     # Download and install gems used inside tests
     $LOAD_PATH.unshift("./spec")