pass -q to curl calls to disable user .curlrc files

PR-URL: npm#2613
Credit: @nlf
Close: npm#2613
Reviewed-by: @ljharb, @wraithgar

README.md

@@ -15,7 +15,7 @@
 You can download & install **`npm`** directly from [**npmjs**.com](https://npmjs.com/) using our custom `install.sh` script:
 
 ```bash
-curl -L https://www.npmjs.com/install.sh | sh
+curl -qL https://www.npmjs.com/install.sh | sh
 ```
 
 #### Node Version Managers
@@ -50,4 +50,4 @@ npm <command>
 ### Acknowledgments
 
 * `npm` is configured to use the **npm Public Registry** at [https://registry.npmjs.org](https://registry.npmjs.org) by default; Usage of this registry is subject to **Terms of Use** available at [https://npmjs.com/policies/terms](https://npmjs.com/policies/terms)
-* You can configure `npm` to use any other compatible registry you prefer. You can read more about configuring third-party registries [here](https://docs.npmjs.com/cli/v7/using-npm/registry)
+* You can configure `npm` to use any other compatible registry you prefer. You can read more about configuring third-party registries [here](https://docs.npmjs.com/cli/v7/using-npm/registry)

scripts/install.sh

@@ -18,7 +18,7 @@ if [ "x$0" = "xsh" ]; then
   # which is a bit cuter.  But on others, &1 is already closed,
   # so catting to another script file won't do anything.
   # Follow Location: headers, and fail on errors
-  curl -f -L -s https://www.npmjs.org/install.sh > npm-install-$$.sh
+  curl -q -f -L -s https://www.npmjs.org/install.sh > npm-install-$$.sh
   ret=$?
   if [ $ret -eq 0 ]; then
     (exit 0)
@@ -134,15 +134,15 @@ fi
 
 # need to echo "" after, because Posix sed doesn't treat EOF
 # as an implied end of line.
-url=`(curl -SsL https://registry.npmjs.org/npm/$t; echo "") \
+url=`(curl -qSsL https://registry.npmjs.org/npm/$t; echo "") \
      | sed -e 's/^.*tarball":"//' \
      | sed -e 's/".*$//'`
 
 ret=$?
 if [ "x$url" = "x" ]; then
   ret=125
   # try without the -e arg to sed.
-  url=`(curl -SsL https://registry.npmjs.org/npm/$t; echo "") \
+  url=`(curl -qSsL https://registry.npmjs.org/npm/$t; echo "") \
        | sed 's/^.*tarball":"//' \
        | sed 's/".*$//'`
   ret=$?
@@ -159,7 +159,7 @@ fi
 echo "fetching: $url" >&2
 
 cd "$TMP" \
-  && curl -SsL -o npm.tgz "$url" \
+  && curl -qSsL -o npm.tgz "$url" \
   && $tar -xzf npm.tgz \
   && cd "$TMP"/package \
   && echo "removing existing npm" \