Fixed illegal char error in is_oss_ok function.

[gxvv]

Describe question

When set NODE_MIRROR to https://npm.taobao.org/mirrors/node/, the n will get an oss link to download node. There are two errors.

Line:404-This line will pass the curl (the value of $GET ) in is_oss_link.
Line:406-The curl can't accept a URL contains \r.
Line:410-This line will pass the wget (the value of $GET ) in is_oss_link.
Line:412-This line is fine.

What my code do

Line:404&410-Use command substitution.
Line:406&412-Remove the illegal character \r .

System environment

OS: Ubuntu 12.04 lts 64bit
n: version 2.1.8

curl version and bash version

curl 7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
Protocols: dict file ftp ftps gopher http https imap imaps ldap pop3 pop3s rtmp rtsp smtp smtps telnet tftp 
Features: GSS-Negotiate IDN IPv6 Largefile NTLM NTLM_WB SSL libz TLS-SRP

GNU bash, version 4.2.25(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[shadowspawn]

This Pull Request has not had any activity in over six months. It would probably fix some specific problems, but I am planning to try a wider fix.

See #560 for open issue. Subscribe to that for updates and/or add 👍 to show interest

Thank you for your contributions.

[shadowspawn]

Prerelease available via npm i n@next for v6. Release notes: https://github.com/tj/n/releases/tag/6.0.0-0