Extract after skipping download for LM example script

Summary: Pull Request resolved: https://github.com/pytorch/fairseq/pull/538

Differential Revision: D14258736

Pulled By: myleott

fbshipit-source-id: ca16355e4c4700fc8eecf2c9374ec170bca826a4

examples/language_model/prepare-wikitext-103.sh

@@ -21,13 +21,13 @@ for ((i=0;i<${#URLS[@]};++i)); do
             echo "$url not successfully downloaded."
             exit -1
         fi
-        if [ ${file: -4} == ".tgz" ]; then
-            tar zxvf $file
-        elif [ ${file: -4} == ".tar" ]; then
-            tar xvf $file
-        elif [ ${file: -4} == ".zip" ]; then
-            unzip $file
-        fi
+    fi
+    if [ ${file: -4} == ".tgz" ]; then
+        tar zxvf $file
+    elif [ ${file: -4} == ".tar" ]; then
+        tar xvf $file
+    elif [ ${file: -4} == ".zip" ]; then
+        unzip $file
     fi
 done
 cd ..