Fix themis/circe postfixes

Author: james-fossa

vendor_download.sh

@@ -78,10 +78,10 @@ case "$(uname -s)" in
     fi
 
     ASSET_POSTFIX="linux"
-    THEMIS_ASSET_POSTFIX="linux-amd64"
+    THEMIS_ASSET_POSTFIX="linux-${LIBC}"
     FICUS_ASSET_POSTFIX="$ARCH-unknown-linux-$LIBC.tar.gz"
     LERNIE_ASSET_POSTFIX="${ARCH}-linux"
-    CIRCE_ASSET_POSTFIX="${ARCH}-unknown-linux-musl"
+    CIRCE_ASSET_POSTFIX="${ARCH}-unknown-linux-${LIBC}"
     ;;
   *)
     echo "Warn: Assuming $(uname -s) is Windows"