安装oracle以后yum 报错 （ImportError: No module named cElementTree）

安装oracle以后yum 安装报错

Plugin "refresh-packagekit" can't be imported
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
Traceback (most recent call last):
File "/usr/bin/yum", line 29, in
yummain.user_main(sys.argv[1:], exit_code=True)
File "/usr/share/yum-cli/yummain.py", line 285, in user_main
errcode = main(args)
File "/usr/share/yum-cli/yummain.py", line 136, in main
result, resultmsgs = base.doCommands()
File "/usr/share/yum-cli/cli.py", line 434, in doCommands
self._getTs(needTsRemove)
File "/usr/lib/python2.6/site-packages/yum/depsolve.py", line 99, in _getTs
self._getTsInfo(remove_only)
File "/usr/lib/python2.6/site-packages/yum/depsolve.py", line 110, in _getTsInfo
pkgSack = self.pkgSack
File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 897, in
pkgSack = property(fget=lambda self: self._getSacks(),
File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 682, in _getSacks
self.repos.populateSack(which=repos)
File "/usr/lib/python2.6/site-packages/yum/repos.py", line 294, in populateSack
sack.populate(repo, mdtype, callback, cacheonly)
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 165, in populate
if self._check_db_version(repo, mydbtype):
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 223, in _check_db_version
return repo._check_db_version(mdtype)
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1256, in _check_db_version
repoXML = self.repoXML
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1455, in
repoXML = property(fget=lambda self: self._getRepoXML(),
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1447, in _getRepoXML
self._loadRepoXML(text=self)
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1437, in _loadRepoXML
return self._groupLoadRepoXML(text, self._mdpolicy2mdtypes())
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1412, in _groupLoadRepoXML
if self._commonLoadRepoXML(text):
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1240, in _commonLoadRepoXML
self._repoXML = self._parseRepoXML(result)
File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1036, in _parseRepoXML
return repoMDObject.RepoMD(self.id, local)
File "/usr/lib/python2.6/site-packages/yum/repoMDObject.py", line 124, in __init__
self.parse(srcfile)
File "/usr/lib/python2.6/site-packages/yum/repoMDObject.py", line 140, in parse
parser = iterparse(infile)
File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1169, in cElementTree_iterparse
_cElementTree_import()
File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1164, in _cElementTree_import
import cElementTree
ImportError: No module named cElementTree

报以上错误时因为在环境变量中设置了 LD_LIBRARY_PATH 。
我是在/etc/profile 中设置的，去掉变量重新打开一个session，echo $LD_LIBRARY_PATH 查看变量为空。再次运行yum 成功。