ruby: Remove outdated patch

packages/ruby/rbinstall.rb.patch

@@ -1,21 +0,0 @@
-diff -u -r ../ruby-2.3.0/tool/rbinstall.rb ./tool/rbinstall.rb
---- ../ruby-2.3.0/tool/rbinstall.rb	2015-11-16 01:33:17.000000000 -0500
-+++ ./tool/rbinstall.rb	2015-12-25 15:43:04.756646343 -0500
-@@ -696,7 +696,7 @@
- # :startdoc:
- 
- install?(:ext, :comm, :gem) do
--  gem_dir = Gem.default_dir
-+  gem_dir = "@TERMUX_PREFIX@/var/lib/gems/2.3.0"
-   directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
-   prepare "default gems", gem_dir, directories
- 
-@@ -732,7 +732,7 @@
- end
- 
- install?(:ext, :comm, :gem) do
--  gem_dir = Gem.default_dir
-+  gem_dir = "@TERMUX_PREFIX@/var/lib/gems/2.3.0"
-   directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
-   prepare "bundle gems", gem_dir, directories
-   install_dir = with_destdir(gem_dir)