[MacPorts] #52921: buildbot: don't say "failed to calculate dependencies" when dependencies are in fact missing

[MacPorts]

#52921: buildbot: don't say "failed to calculate dependencies" when dependencies
are in fact missing
----------------------------+---------------------
 Reporter:  mojca           |      Owner:  admin@…
     Type:  defect          |     Status:  new
 Priority:  Low             |  Milestone:
Component:  server/hosting  |    Version:
 Keywords:  buildbot        |       Port:
----------------------------+---------------------
 We need to fix error reports about dependencies.

 For example:
 * https://lists.macports.org/pipermail/macports-
 builds/2016-November/000957.html
 says
 {{{
 Building 'py26-m2crypto' ... [ERROR] (failed to calculate dependencies)
 }}}
 but
 [https://build.macports.org/builders/ports-10.12_x86_64-builder/builds/13167/steps
 /install-dependencies/logs/stdio in reality] it is:
 {{{
 Error: Dependency 'py26-typing' not found.
 Error: mportdepends py26-m2crypto activate failed.
 Calculating dependencies for 'py26-m2crypto' failed, aborting.
 ./mpbb/mpbb: error: `install-dependencies' failed to run successfully
 }}}

 In our reports we should distinguish between non-existent dependencies and
 other problems. Or at least reword the error message and add a possible
 reason.

--
Ticket URL: <https://trac.macports.org/ticket/52921>
MacPorts <https://www.macports.org/>
Ports system for macOS