Fix handling of variables - use local

tools/travis_install_optional.sh

@@ -6,17 +6,11 @@ tools/header.py "Install optional dependencies"
 # Install Qt and then update the Matplotlib settings
 if [[ $TRAVIS_PYTHON_VERSION == 2.7* ]]; then
     sudo apt-get install -q python-qt4
-    export MPL_QT_API=PyQt4
-    export MPL_DIR=$HOME/.matplotlib
-    export QT_API=pyqt
 
 else
     sudo apt-get install -q libqt4-dev
     pip install PySide $WHEELHOUSE
     python ~/virtualenv/python${TRAVIS_PYTHON_VERSION}/bin/pyside_postinstall.py -install
-    export MPL_QT_API=PySide
-    export MPL_DIR=$HOME/.config/matplotlib
-    export QT_API=pyside
 fi
 
 # imread does NOT support py3.2

tools/travis_test.sh

@@ -1,6 +1,17 @@
 #!/usr/bin/env bash
 set -ex
 
+if [[ $TRAVIS_PYTHON_VERSION == 2.7* ]]; then
+    MPL_QT_API=PyQt4
+    MPL_DIR=$HOME/.matplotlib
+    export QT_API=pyqt
+
+else
+    MPL_QT_API=PySide
+    MPL_DIR=$HOME/.config/matplotlib
+    export QT_API=pyside
+fi
+
 # Matplotlib settings - do not show figures during doc examples
 mkdir -p $MPL_DIR
 touch $MPL_DIR/matplotlibrc