Machine Agent URL returns 403

The cookbook is not able to download from `"https://packages.appdynamics.com/machine/4.1.3.1/MachineAgent-4.1.3.1.zip"`

This is likely because the filename isn't `MachineAgent-4.1.3.1.zip` but rather `machineagent-bundle-64bit-linux-4.3.7.1.zip`

```
Net::HTTPServerException
------------------------
403 "Forbidden"

Resource Declaration:
---------------------
# In /tmp/kitchen/cache/cookbooks/appdynamics/recipes/machine_agent.rb

45: remote_file agent_zip do
46: source package_source
47: checksum agent['checksum']
48: backup false
49: mode '0444'
50: notifies :run, 'execute[unzip-appdynamics-machine-agent]', :immediately
51: end
52:

Compiled Resource:
------------------
# Declared in /tmp/kitchen/cache/cookbooks/appdynamics/recipes/machine_agent.rb:45:in `from_file'

remote_file("/tmp/kitchen/cache/AppDynamicsMachineAgent.zip") do
provider Chef::Provider::RemoteFile
action [:create]
default_guard_interpreter :default
source ["https://packages.appdynamics.com/machine/4.1.3.1/MachineAgent-4.1.3.1.zip"]
use_etag true
use_last_modified true
declared_type :remote_file
cookbook_name "appdynamics"
recipe_name "machine_agent"
checksum nil
mode "0444"
remote_domain nil
remote_user nil
path "/tmp/kitchen/cache/AppDynamicsMachineAgent.zip"
owner nil
group nil
verifications []
end

System Info:
------------
chef_version=13.6.4
platform=ubuntu
platform_version=16.04
ruby=ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-linux]
program_name=chef-client worker: ppid=2753;start=20:49:42;
executable=/opt/chef/bin/chef-client
```

Start in recipes/machine_agent.rb at the remote_file declaration around line 45, then trace package_source and agent['checksum']. Verify the configured Machine Agent URL against the package name described in the issue and confirm the cookbook can download the archive without a 403 during a cookbook converge.

Written by the indexing model from the issue text.