Use versioncmp to check Puppet version for 4.10.x compatibility

`Puppet.version.to_f` on Puppet 4.10.0 will evaluate to `4.1`, causing
test and behavioural changes when conditionals check that the version is
equal or greater than versions such as `4.3`.

Version comparisons that are vulnerable to this have been changed to use
Puppet's versioncmp implementation, while most others only check for
for major version boundaries which is safe.

Author: domcleal

lib/puppet-syntax/manifests.rb

@@ -59,7 +59,7 @@ def check(filelist)
     private
     def validate_manifest(file)
       Puppet[:parser] = 'future' if PuppetSyntax.future_parser and Puppet::PUPPETVERSION.to_i < 4
-      Puppet[:app_management] = true if PuppetSyntax.app_management && (Puppet::PUPPETVERSION.to_f >= 4.3 && Puppet::PUPPETVERSION.to_i < 5)
+      Puppet[:app_management] = true if PuppetSyntax.app_management && (Puppet::Util::Package.versioncmp(Puppet.version, '4.3.0') >= 0 && Puppet.version.to_i < 5)
       Puppet::Face[:parser, :current].validate(file)
     end
   end

lib/puppet-syntax/tasks/puppet-syntax.rb

@@ -54,7 +54,7 @@ def initialize(*args)
 'true'. The `future_parser setting will be ignored.
             EOS
           end
-          if Puppet::PUPPETVERSION.to_f < 4.3 and PuppetSyntax.app_management
+          if Puppet::Util::Package.versioncmp(Puppet.version, '4.3.0') < 0 and PuppetSyntax.app_management
             $stderr.puts <<-EOS
 [WARNING] Puppet `app_management` has been detected but the Puppet
 version is less then 4.3.  The `app_management` setting will be ignored.

spec/puppet-syntax/manifests_spec.rb

@@ -155,7 +155,7 @@
       before(:each) {
         PuppetSyntax.app_management = true
       }
-      if Puppet::PUPPETVERSION.to_f >= 4.3
+      if Puppet::Util::Package.versioncmp(Puppet.version, '4.3.0') >= 0
         it 'should successfully parse an application manifest on Puppet >= 4.3.0' do
           expect(PuppetSyntax.app_management).to eq(true)