rake tasks that should work on windows/msys

Rakefile

@@ -13,9 +13,6 @@ require 'rbconfig'
 include Config
 ENV['TEST_MODE'] = 'TRUE'
 
-gem_command = "gem"
-gem_command = "gem1.9" if $0.match(/1\.9$/) # use gem1.9 if we used rake1.9
-
 desc "Test the MongoDB Ruby driver."
 task :test do
   puts "\nThis option has changed."
@@ -96,20 +93,16 @@ namespace :gem do
 
   desc "Install the gem locally"
   task :install do
-    sh <<EOS
-#{gem_command} build mongo-ruby-driver.gemspec &&
-    #{gem_command} install mongo-*.gem &&
-    rm mongo-*.gem
-EOS
+    system "gem build mongo-ruby-driver.gemspec"
+    system "gem install mongo-*.gem"
+    system "rm mongo-*.gem"
   end
 
   desc "Install the optional c extensions"
   task :install_extensions do
-    sh <<EOS
-#{gem_command} build mongo-extensions.gemspec &&
-    #{gem_command} install mongo_ext-*.gem &&
-    rm mongo_ext-*.gem
-EOS
+    system "gem build mongo-extensions.gemspec"
+    system "gem install mongo_ext-*.gem"
+    system "rm mongo_ext-*.gem"
   end
 
 end