[rubygems/rubygems] Don't show bug report template when GEM_HOME has no writable bit

Instead, don't check that at all and proceed. If something fails to be
written inside GEM_HOME, we'll eventually fail with a proper permissions
error.

In addition to that, the writable bit in GEM_HOME is not even reliable,
because only the immediate parent is actually checked when writing. For
example,

```
$ mkdir -p foo/bar
$ chmod -w foo
$ touch foo/bar/baz # writes without issue
```

https://github.com/rubygems/rubygems/commit/4bced7ac73

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/bundler/rubygems_gem_installer.rb b/lib/bundler/rubygems_gem_installer.rb
index 4d0e1c3fcc..8463b24bfa 100644
--- a/lib/bundler/rubygems_gem_installer.rb
+++ b/lib/bundler/rubygems_gem_installer.rb
@@ -45,6 +45,14 @@ module Bundler
       spec
     end
 
+    def pre_install_checks
+      super
+    rescue Gem::FilePermissionError
+      # Ignore permission checks in RubyGems. Instead, go on, and try to write
+      # for real. We properly handle permission errors when they happen.
+      nil
+    end
+
     def generate_plugins
       return unless Gem::Installer.instance_methods(false).include?(:generate_plugins)