我正在配置CentOS 6服务器。我正在尝试安装rvm，但出现错误。当我尝试在服务器上安装rvm时。谁能知道原因吗？
step1。
gpg --keyserver hkp://pool.sks-keyservers.net:80 --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB
输出
gpg: key D39DC0E3: "Michal Papis (RVM signing) <[email protected]>" not changed
gpg: key D39DC0E3: "Totally Legit Signing Key <[email protected]>" not changed
gpg: key 39499BDB: "Piotr Kuczynski <[email protected]>" not changed
gpg: Total number processed: 3
gpg: unchanged: 3
第2步（出现错误）
curl -sSL https://get.rvm.io | bash -s stable
输出
WARN: ...the preceeding error with code 35 occurred while fetching https://api.github.com/repos/rvm/rvm/tags
curl: (35) SSL connect error
WARN: ...the preceeding error with code 35 occurred while fetching https://api.bitbucket.org/2.0/repositories/mpapis/rvm/refs/tags?sort=-name&pagelen=20
ERROR: Exhausted all sources trying to fetch version 'latest' of RVM!
服务器中cURL的版本是什么？