yum 安装错误的解决办法

需要在公司的机器上安装git，可是在执行yum install的时候却发生了下边的错误。
Traceback (most recent call last):
File "/usr/bin/yum", line 29, in <module>                                                           
    yummain.user_main(sys.argv[1:], exit_code=True)                                                   
File "/usr/share/yum-cli/yummain.py", line 229, in user_main                                        
    errcode = main(args)                                                                              
File "/usr/share/yum-cli/yummain.py", line 104, in main                                             
    result, resultmsgs = base.doCommands()                                                            
File "/usr/share/yum-cli/cli.py", line 339, in doCommands                                           
    self._getTs(needTsRemove)                                                                         
File "/usr/lib/python2.5/site-packages/yum/depsolve.py", line 101, in _getTs                        
    self._getTsInfo(remove_only)                                                                      
File "/usr/lib/python2.5/site-packages/yum/depsolve.py", line 112, in _getTsInfo                    
    pkgSack = self.pkgSack                                                                            
File "/usr/lib/python2.5/site-packages/yum/__init__.py", line 592, in <lambda>                      
    pkgSack = property(fget=lambda self: self._getSacks(),                                            
File "/usr/lib/python2.5/site-packages/yum/__init__.py", line 435, in _getSacks                     
    self.repos.populateSack(which=repos)                                                              
File "/usr/lib/python2.5/site-packages/yum/repos.py", line 251, in populateSack                     
    sack.populate(repo, mdtype, callback, cacheonly)                                                  
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 160, in populate                       
    if self._check_db_version(repo, mydbtype):                                                        
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 217, in _check_db_version              
    return repo._check_db_version(mdtype)                                                             
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 1119, in _check_db_version             
    repoXML = self.repoXML                                                                            
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 1277, in <lambda>                      
    repoXML = property(fget=lambda self: self._getRepoXML(),                                          
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 1269, in _getRepoXML                   
    self._loadRepoXML(text=self)                                                                      
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 1259, in _loadRepoXML                  
    return self._groupLoadRepoXML(text, ["primary"])                                                  
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 1243, in _groupLoadRepoXML             
    if self._commonLoadRepoXML(text):                                                                 
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 1112, in _commonLoadRepoXML            
    if not self._groupCheckDataMDNewer():                                                             
File "/usr/lib/python2.5/site-packages/yum/yumRepo.py", line 994, in _groupCheckDataMDNewer         
    old_repo_XML.timestamp > self.repoXML.timestamp):                                                 
AttributeError: 'NoneType' object has no attribute 'timestamp'

在网上查找解决办法，将 /etc/yum.conf 文件中的 plugins 设为 0 即可。