DEV: use common root-environment scons in travis.

scons-driven builds for Python 3 need scons from another (root)
environment, because scons is so far only available for Python 2.

Author: pavoljuhas

Diff for: .travis.yml

@@ -59,7 +59,10 @@ before_install:
   - $NOMC || popd
   - $NOMC || export PATH="${HOME}/mc/bin:${PATH}"
   - $NOMC || conda update --yes conda
-  - $NOMC || conda install --yes conda-build jinja2
+  - $NOMC || conda install --yes conda-build jinja2 scons
+  # Make scons available globally.
+  - $NOMC || mkdir -p ~/bin
+  - $NOMC || cp ~/mc/bin/scons ~/bin/
   - $NOMC || conda create --name=testenv --yes python=${MYPYTHON_VERSION} coverage
   - $NOMC || conda config --add channels diffpy
 

Diff for: conda-recipe/meta.yaml

@@ -9,8 +9,6 @@ source:
   git_url: ..
 
 build:
-  #preserve_egg_dir: True
-
   # If this is a new build for the same version, increment the build
   # number. If you do not include this key, it defaults to 0.
   number: 0
@@ -22,7 +20,6 @@ requirements:
     - numpy 1.9.2
     - libobjcryst 2015.1.*
     - boost-all 1.59.0
-    - scons
 
   run:
     - python