[Unix#run_command] Remove Ruby 1.8.7 check

Signed-off-by: David Crosby <dcrosby@fb.com>

lib/mixlib/shellout/unix.rb

@@ -20,11 +20,6 @@ module Mixlib
   class ShellOut
     module Unix
 
-      # "1.8.7" as a frozen string. We use this with a hack that disables GC to
-      # avoid segfaults on Ruby 1.8.7, so we need to allocate the fewest
-      # objects we possibly can.
-      ONE_DOT_EIGHT_DOT_SEVEN = "1.8.7".freeze
-
       # Option validation that is unix specific
       def validate_options(opts)
         if opts[:elevated]
@@ -99,12 +94,6 @@ def run_command
 
         configure_parent_process_file_descriptors
 
-        # Ruby 1.8.7 and 1.8.6 from mid 2009 try to allocate objects during GC
-        # when calling IO.select and IO#read. Disabling GC works around the
-        # segfault, but obviously it's a bad workaround. We no longer support
-        # 1.8.6 so we only need this hack for 1.8.7.
-        GC.disable if RUBY_VERSION == ONE_DOT_EIGHT_DOT_SEVEN
-
         # CHEF-3390: Marshall.load on Ruby < 1.8.7p369 also has a GC bug related
         # to Marshall.load, so try disabling GC first.
         propagate_pre_exec_failure