Correct resource limit defaults

[michaelklishin]

Proposed Changes

This reduces some resource limit defaults: Erlang distribution buffer size and the max number of processes. They were bumped to x10 the values in 118b448 by mistake and these values are somewhat unreasonable.

Types of Changes

• Bug fix (non-breaking change which fixes issue Default distribution buffer size and max process limit are unintentionally excessive #1659
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (correction or otherwise)
• Cosmetics (whitespace, appearance)

Checklist

• I have read the CONTRIBUTING.md document
• I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• All tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in related repositories

Further Comments

Closes #1659.