use curl not wget to fetch flower data

curl is pre-installed on the mac and the tensorflow docker image. wget
is not. This change allows this script to run on a stock mac, or in the
tensorflow docker image

inception/inception/data/download_and_preprocess_flowers.sh

@@ -53,7 +53,7 @@ cd "${DATA_DIR}"
 TARBALL="flower_photos.tgz"
 if [ ! -f ${TARBALL} ]; then
   echo "Downloading flower data set."
-  wget -O ${TARBALL} "${DATA_URL}"
+  curl -o ${TARBALL} "${DATA_URL}"
 else
   echo "Skipping download of flower data."
 fi

inception/inception/data/download_and_preprocess_flowers_mac.sh

@@ -53,7 +53,7 @@ cd "${DATA_DIR}"
 TARBALL="flower_photos.tgz"
 if [ ! -f ${TARBALL} ]; then
   echo "Downloading flower data set."
-  wget -O ${TARBALL} "${DATA_URL}"
+  curl -o ${TARBALL} "${DATA_URL}"
 else
   echo "Skipping download of flower data."
 fi