We need to checkout before BundledGem.dummy_gemspec checking.

  When newer version released rather than gems/bundled_gems defined,
  `spec.version == Gem::Version.new(v)` always abort like:

  ```
  Unexpected versions between bundled_gems:3.0.4 and gemspec:3.1.0
  ```

1 files changed, 10 insertions, 6 deletions

diff --git a/tool/fetch-bundled_gems.rb b/tool/fetch-bundled_gems.rb
index 6f70bd076a..bdbf9fd2a4 100755
--- a/tool/fetch-bundled_gems.rb
+++ b/tool/fetch-bundled_gems.rb
@@ -20,10 +20,20 @@ else
   puts "retrieving #{n} ..."
   system(*%W"git clone #{u} #{n}") or abort
 end
+
 if r
   puts "fetching #{r} ..."
   system("git", "fetch", "origin", r, chdir: n) or abort
+end
+
+c = r || "v#{v}"
+checkout = %w"git -c advice.detachedHead=false checkout"
+puts "checking out #{c} (v=#{v}, r=#{r}) ..."
+unless system(*checkout, c, "--", chdir: n)
+  abort if r or !system(*checkout, v, "--", chdir: n)
+end
 
+if r
   unless File.exist? "#{n}/#{n}.gemspec"
     require_relative "lib/bundled_gem"
     BundledGem.dummy_gemspec("#{n}/#{n}.gemspec")
@@ -34,9 +44,3 @@ if r
   spec = Gem::Specification.load("#{n}/#{n}.gemspec")
   abort "Unexpected versions between bundled_gems:#{v} and gemspec:#{spec.version}" unless spec.version == Gem::Version.new(v)
 end
-c = r || "v#{v}"
-checkout = %w"git -c advice.detachedHead=false checkout"
-puts "checking out #{c} (v=#{v}, r=#{r}) ..."
-unless system(*checkout, c, "--", chdir: n)
-  abort if r or !system(*checkout, v, "--", chdir: n)
-end