alpine: Require curl-ca-bundle with +ssl.

[fhgwright]

Some server certificates aren't based on root CAs included with the OS (at least for some OS versions). Installing curl-ca-bundle typically provides the needed root CAs, and isn't very expensive. Since other common installs already depend on curl-ca-bundle, it's likely that Alpine has been opportunistically getting it in most cases.

Theoretically, this change should get a revbump to ensure that the dependency is included. But since most installations probably already have curl-ca-bundle installed, it's not really worth a rebuild to fix the rare cases.

Also removes redundant "platforms darwin" (to get rid of a lint warning).

TESTED:
Correctly shows dependency iff +ssl.
Active curl-ca-bundle fixes access to at least one server.

Description

Type(s)

• bugfix
• enhancement
• security fix

Tested on

OS X 10.9.5 13F1911, x86_64, Xcode 6.2 6C131e

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• [N/A] referenced existing tickets on Trac with full URL in commit message?
• checked your Portfile with port lint?
• tried existing tests with sudo port test?
• [NO] tried a full install with sudo port -vst install?
• [NO] tested basic functionality of all binary files?
• [NO] checked that the Portfile's most important variants haven't been broken?

NOTE: Abbreviated testing due to limited nature of change.

[macportsbot]

Notifying maintainers:
@jerryyhom for port alpine.
@jcvernaleo for port alpine.