sharness: make put sharness test easier to follow

Address https://github.com/ipfs/go-ipfs/pull/3931#pullrequestreview-46345532

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>

test/sharness/t0111-gateway-writeable.sh

@@ -108,11 +108,11 @@ test_expect_success "Replacing a file with PUT gives us the hash of the new tree
   echo "PUT $URL" &&
   curl -svX PUT --data-binary @infile3 "$URL" 2>curl_putExisting.out &&
   grep "HTTP/1.1 201 Created" curl_putExisting.out &&
-  LOCATION=$(grep Location curl_putExisting.out) &&
-  IPFS_HASH=$(grep Ipfs-Hash curl_putExisting.out) &&
-  HASH=$(expr "$LOCATION" : "< Location: /ipfs/\(.*\)/test/test.txt") &&
-  IPFS_HASH=$(expr "$IPFS_HASH" : "< Ipfs-Hash: \(\w*\)") &&
-  [ "$HASH" = "$IPFS_HASH" ]
+  LOCATION_HEADER=$(grep Location curl_putExisting.out) &&
+  IPFS_HASH_HEADER=$(grep Ipfs-Hash curl_putExisting.out) &&
+  HASH1=$(expr "$LOCATION_HEADER" : "< Location: /ipfs/\(.*\)/test/test.txt") &&
+  HASH2=$(expr "$IPFS_HASH_HEADER" : "< Ipfs-Hash: \(\w*\)") &&
+  [ "$HASH2" = "$HASH1" ]
 '
 
 test_expect_success "We can HTTP GET file just replaced" '