[Python] Clarify in development.rst that virtualenv cannot be used with miniconda/Anaconda

[asfimport]

Per mailing list thread on 2018-12-25

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

PRs and other links:

• GitHub Pull Request #3264

_{Note: This issue was originally created as ARROW-4116. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 3264
#3264