(#19663) Remove --include-dependencies flag in gem package provider

Without this patch applied the gem package provider will always pass the
`--include-dependencies` flag to the gem command.  This flag has been
deprecated in Rubygems for quite some time.  The behavior of including
dependencies when installing a gem has been the default for some time,
so this patch does not change behavior for any recent version of
Rubygems since 0.9.5.

Here is the comment from the pull request:

This is a good explanation about the option: rubygems/rubygems#385

It was already deprecated since rubygems 0.9.5 and was the default
option since then.

Unless someone is using a version of rubygems from mid 2007, this option
is never being used
https://github.com/rubygems/rubygems/blob/a00fc76fb6b959385331715c500af1eb25590405/History.txt#L1451

lib/puppet/provider/package/gem.rb

@@ -72,8 +72,6 @@ def self.instances(justme = false)
   def install(useversion = true)
     command = [command(:gemcmd), "install"]
     command << "-v" << resource[:ensure] if (! resource[:ensure].is_a? Symbol) and useversion
-    # Always include dependencies
-    command << "--include-dependencies"
 
     if source = resource[:source]
       begin

spec/unit/provider/package/gem_spec.rb

@@ -29,38 +29,33 @@
       provider.install
     end
 
-    it "should specify that dependencies should be included" do
-      provider.expects(:execute).with { |args| args[2] == "--include-dependencies" }.returns ""
-      provider.install
-    end
-
     it "should specify that documentation should not be included" do
-      provider.expects(:execute).with { |args| args[3] == "--no-rdoc" }.returns ""
+      provider.expects(:execute).with { |args| args[2] == "--no-rdoc" }.returns ""
       provider.install
     end
 
     it "should specify that RI should not be included" do
-      provider.expects(:execute).with { |args| args[4] == "--no-ri" }.returns ""
+      provider.expects(:execute).with { |args| args[3] == "--no-ri" }.returns ""
       provider.install
     end
 
     it "should specify the package name" do
-      provider.expects(:execute).with { |args| args[5] == "myresource" }.returns ""
+      provider.expects(:execute).with { |args| args[4] == "myresource" }.returns ""
       provider.install
     end
 
     describe "when a source is specified" do
       describe "as a normal file" do
         it "should use the file name instead of the gem name" do
           resource[:source] = "/my/file"
-          provider.expects(:execute).with { |args| args[3] == "/my/file" }.returns ""
+          provider.expects(:execute).with { |args| args[2] == "/my/file" }.returns ""
           provider.install
         end
       end
       describe "as a file url" do
         it "should use the file name instead of the gem name" do
           resource[:source] = "file:///my/file"
-          provider.expects(:execute).with { |args| args[3] == "/my/file" }.returns ""
+          provider.expects(:execute).with { |args| args[2] == "/my/file" }.returns ""
           provider.install
         end
       end
@@ -73,7 +68,7 @@
       describe "as a non-file and non-puppet url" do
         it "should treat the source as a gem repository" do
           resource[:source] = "http://host/my/file"
-          provider.expects(:execute).with { |args| args[3..5] == ["--source", "http://host/my/file", "myresource"] }.returns ""
+          provider.expects(:execute).with { |args| args[2..4] == ["--source", "http://host/my/file", "myresource"] }.returns ""
           provider.install
         end
       end