修改python软连接导致yum等无法正常运行

bcc需要py3，于是把python软连接对应版本改到3上面去，结果导致yum等依赖py2的程序无法正常运行

修改方式

# yum install rpm-build -y
  File "/bin/yum", line 30
    except KeyboardInterrupt, e:
                            ^
SyntaxError: invalid syntax

 vi /usr/bin/yum
#!/usr/bin/python2.7 #根据实际的版本来


  File "/usr/libexec/urlgrabber-ext-down", line 28
    except OSError, e:
                  ^
SyntaxError: invalid syntax


Exiting on user cancel
# vi /usr/libexec/urlgrabber-ext-down