guest: redhat: reset back to pre-EL8 modifications

This is a revert of cd31a47 ac732ac and de0dfd7. In those commits we
were trying to support CentOS and RHEL 8 better, but the changes ended
up being mostly useful only for CentOS. Now that CentOS has it's own
flavor detection in Vagrant and centos_8 and rhel_8 are properly
supported [1] we definitely don't need de0dfd7 and we can also move
the redhat module back to just supporting RHEL since dd02e09 handles
CentOS for us.

[1] hashicorp/vagrant@5104d07

lib/vagrant-sshfs/cap/guest/redhat/sshfs_client.rb

@@ -3,27 +3,13 @@ module GuestRedHat
     module Cap
       class SSHFSClient
         def self.sshfs_install(machine)
-
-          rhel_version = machine.guest.capability("flavor")
-
-          # Handle the case where Vagrant doesn't yet know how to
-          # detect and return :rhel_8 https://github.com/hashicorp/vagrant/pull/11453
-          if Gem::Version.new(Vagrant::VERSION) < Gem::Version.new('2.2.8')
-            rhel_version = vagrant_lt_228_flavor_compat(machine)
+          # Install epel rpm if not installed
+          if !epel_installed(machine)
+            epel_install(machine)
           end
 
-          case rhel_version
-            when :rhel_8
-              # No need to install epel. fuse-sshfs comes from the PowerTools repo
-              # https://bugzilla.redhat.com/show_bug.cgi?id=1758884
-              machine.communicate.sudo("yum -y install --enablerepo=PowerTools fuse-sshfs")
-            when :rhel_7, :rhel # rhel7 and rhel6
-              # Install fuse-sshfs from epel
-              if !epel_installed(machine)
-                epel_install(machine)
-              end
-              machine.communicate.sudo("yum -y install fuse-sshfs")
-          end
+          # Install sshfs (comes from epel repos)
+          machine.communicate.sudo("yum -y install fuse-sshfs")
         end
 
         def self.sshfs_installed(machine)
@@ -37,23 +23,11 @@ def self.epel_installed(machine)
         end
 
         def self.epel_install(machine)
-          machine.communicate.sudo("yum -y install epel-release")
-        end
-
-        def self.vagrant_lt_228_flavor_compat(machine)
-          # This is a compatibility function to handle RHEL8 for
-          # vagrant versions that didn't include:
-          # https://github.com/hashicorp/vagrant/pull/11453
-          output = ""
-          machine.communicate.sudo("cat /etc/redhat-release") do |_, data|
-            output = data
-          end
-          if output =~ /(CentOS|Red Hat Enterprise|Scientific|Cloud|Virtuozzo)\s*Linux( .+)? release 8/i
-            return :rhel_8
-          elsif output =~ /(CentOS|Red Hat Enterprise|Scientific|Cloud|Virtuozzo)\s*Linux( .+)? release 7/i
-            return :rhel_7
-          else
-            return :rhel
+          case machine.guest.capability("flavor")
+            when :rhel_7
+              machine.communicate.sudo("rpm -ivh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm")
+            when :rhel # rhel6
+              machine.communicate.sudo("rpm -ivh https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm")
           end
         end
       end