ARROW-3565: [Python] Pin tensorflow to 1.11.0 in manylinux1 container

Verified that this does not increase the current pinned numpy version.

Author: Korn, Uwe <Uwe.Korn@blue-yonder.com>

Closes #2797 from xhochy/ARROW-3565 and squashes the following commits:

0307343a1 <Korn, Uwe> ARROW-3565:  Pin tensorflow to 1.11.0 in manylinux1 container
diff --git a/python/manylinux1/build_arrow.sh b/python/manylinux1/build_arrow.sh
index d99f072..4481652 100755
--- a/python/manylinux1/build_arrow.sh
+++ b/python/manylinux1/build_arrow.sh
@@ -60,7 +60,7 @@
     # TensorFlow is not supported for Python 2.7 with unicode width 16 or with Python 3.7
     if [ $PYTHON != "2.7" ] || [ $U_WIDTH = "32" ]; then
       if [ $PYTHON != "3.7" ]; then
-        $PIP install --ignore-installed --upgrade tensorflow
+        $PIP install tensorflow==1.11.0
       fi
     fi
 
@@ -109,9 +109,6 @@
 
     echo "=== (${PYTHON}) Test the existence of optional modules ==="
     $PIP install -r requirements.txt
-    PATH="$PATH:${CPYTHON_PATH}/bin" $PYTHON_INTERPRETER -c "import pyarrow.orc"
-    PATH="$PATH:${CPYTHON_PATH}/bin" $PYTHON_INTERPRETER -c "import pyarrow.parquet"
-    PATH="$PATH:${CPYTHON_PATH}/bin" $PYTHON_INTERPRETER -c "import pyarrow.plasma"
 
     echo "=== (${PYTHON}) Tag the wheel with manylinux1 ==="
     mkdir -p repaired_wheels/
@@ -121,6 +118,10 @@
     source /venv-test-${PYTHON}-${U_WIDTH}/bin/activate
     pip install repaired_wheels/*.whl
 
+    PATH="$PATH:${CPYTHON_PATH}/bin" $PYTHON_INTERPRETER -c "import pyarrow.orc"
+    PATH="$PATH:${CPYTHON_PATH}/bin" $PYTHON_INTERPRETER -c "import pyarrow.parquet"
+    PATH="$PATH:${CPYTHON_PATH}/bin" $PYTHON_INTERPRETER -c "import pyarrow.plasma"
+
     # The TensorFlow test will be skipped here, since TensorFlow is not
     # manylinux1 compatible; however, the wheels will support TensorFlow on
     # a TensorFlow compatible system