update pip if it is out of date

bin/compile

@@ -27,6 +27,8 @@ PROFILE_PATH="$BUILD_DIR/.profile.d/python.sh"
 # Python version. This will be used in the future to specify custom Pythons.
 DEFAULT_PYTHON_VERSION="python-2.7.3"
 PYTHON_EXE="/app/.heroku/python/bin/python"
+PIP_VERSION="1.3.1"
+DISTRIBUTE_VERSION="0.6.35"
 
 # Sanitizing environment variables.
 unset GIT_DIR PYTHONHOME PYTHONPATH LD_LIBRARY_PATH LIBRARY_PATH
@@ -124,22 +126,25 @@ if [ ! "$SKIP_INSTALL" ]; then
   echo $PYTHON_VERSION > .heroku/python-version
   WORKING_DIR=$(pwd)
 
-  # Prepare it for the real world
-  puts-step "Installing Distribute (0.6.35)"
-  cd $ROOT_DIR/vendor/distribute-0.6.35/
-  python setup.py install  &> /dev/null
-  cd $WORKING_DIR
-
-  puts-step "Installing Pip (1.3.1)"
-  cd $ROOT_DIR/vendor/pip-1.3.1/
-  python setup.py install  &> /dev/null
-  cd $WORKING_DIR
-
   hash -r
 else
   puts-step "Using Python runtime ($PYTHON_VERSION)"
 fi
 
+# If Pip isn't up to date:
+if [[ ! $(pip --version) == *$PIP_VERSION* ]]; then
+  # Prepare it for the real world
+  puts-step "Installing Distribute ($DISTRIBUTE_VERSION)"
+  cd $ROOT_DIR/vendor/distribute-$DISTRIBUTE_VERSION/
+  python setup.py install  &> /dev/null
+  cd $WORKING_DIR
+
+  puts-step "Installing Pip ($PIP_VERSION)"
+  cd $ROOT_DIR/vendor/pip-$PIP_VERSION/
+  python setup.py install  &> /dev/null
+  cd $WORKING_DIR
+fi
+
 set -e
 
 # Pylibmc support.