Add custom upload rules for deb packages

As of beaver v0.6.0 we have the option to use the `-C` option to specify
the repo to which a package should be uploaded.  This patch adds a small
helper script to decide the repo based on the version tag: anything with
a whole word equal `alpha`, `beta` or `rc` will go to the `prerelease`
repo, while a package built from any other version tag will go to the
`release` repo.  Travis CI config has been updated to use this script
for the deployment stage.

This should allow us to make trial package release tags along the lines
of `X.y.z-0tsunamiN+rc.1`, validate they work, and then follow up with a
final `X.y.z-0tsunamiN` tag to mark the final release package.

.travis.yml

@@ -22,7 +22,7 @@ script:
 
 deploy:
     provider: script
-    script: beaver bintray upload -d sociomantic-tsunami/mxnet/libmxnet build/last/pkg/*.deb
+    script: ./upload-tsunami-package
     skip_cleanup: true
     on:
         tags: true

upload-tsunami-package

@@ -0,0 +1,55 @@
+#!/bin/sh
+
+################################################################################
+#
+# Helper script to upload tsunami libmxnet packages to the correct bintray repo
+#
+################################################################################
+#
+# This script parses the `TRAVIS_TAG` (i.e. the git tag containing the version
+# of the package that has been built) to determine where to upload the package:
+#
+#   * package versions containing any of the words `alpha`, `beta` or `rc`
+#     (whether in the upstream version or the package iteration) will be
+#     uploaded to the `prerelease` repo
+#
+#   * otherwise, it is inferred the package is a stable release, and it
+#     will be uploaded to the `release` repo
+#
+################################################################################
+#
+# Boost Software License - Version 1.0 - August 17th, 2003
+#
+# Permission is hereby granted, free of charge, to any person or organization
+# obtaining a copy of the software and accompanying documentation covered by
+# this license (the "Software") to use, reproduce, display, distribute,
+# execute, and transmit the Software, and to prepare derivative works of the
+# Software, and to permit third-parties to whom the Software is furnished to
+# do so, all subject to the following:
+#
+# The copyright notices in the Software and this entire statement, including
+# the above license grant, this restriction and the following disclaimer,
+# must be included in all copies of the Software, in whole or in part, and
+# all derivative works of the Software, unless such copies or derivative
+# works are solely in the form of machine-executable object code generated by
+# a source language processor.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+# SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+# FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+# DEALINGS IN THE SOFTWARE.
+#
+################################################################################
+
+set -ex
+
+if echo "$TRAVIS_TAG" | grep -qe '\<alpha\|beta\|rc\>'; then
+	UPLOAD_DESTINATION=prerelease
+else
+	UPLOAD_DESTINATION=release
+fi
+
+beaver bintray upload -C "$UPLOAD_DESTINATION" -d sociomantic-tsunami/mxnet/libmxnet build/last/pkg/*.deb