Update nvm.sh

fix download

Author: Buguin

nvm.sh

@@ -115,29 +115,6 @@ nvm_get_latest() {
   nvm_echo "${NVM_LATEST_URL##*/}"
 }
 
-nvm_download_back() {
-  local CURL_COMPRESSED_FLAG
-  if nvm_has "curl"; then
-    if nvm_curl_use_compression; then
-      CURL_COMPRESSED_FLAG="--compressed"
-    fi
-    curl --fail ${CURL_COMPRESSED_FLAG:-} -q "$@"
-  elif nvm_has "wget"; then
-    # Emulate curl with wget
-    ARGS=$(nvm_echo "$@" | command sed -e 's/--progress-bar /--progress=bar /' \
-                            -e 's/--compressed //' \
-                            -e 's/--fail //' \
-                            -e 's/-L //' \
-                            -e 's/-I /--server-response /' \
-                            -e 's/-s /-q /' \
-                            -e 's/-sS /-nv /' \
-                            -e 's/-o /-O /' \
-                            -e 's/-C - /-c /')
-    # shellcheck disable=SC2086
-    eval wget $ARGS
-  fi
-}
-
 #################################################################################
 #  The software package download function has the same function as nvm_download.
 #  this function will return the HTTP status after download file.If the download is successful,