Update lxml to 3.3.5

docs/shared/requirements.txt

@@ -31,7 +31,7 @@ feedparser==5.1.3
 fs==0.4.0
 GitPython==0.3.2.RC1
 glob2==0.3
-lxml==3.0.1
+lxml==3.3.5
 mako==0.7.3
 Markdown==2.2.1
 mock==1.0.1

requirements/edx-sandbox/post.txt

@@ -6,4 +6,4 @@
 
 # Packages to install in the Python sandbox for secured execution.
 scipy==0.14.0
-lxml==3.0.1
+lxml==3.3.5

requirements/edx/base.txt

@@ -40,7 +40,7 @@ GitPython==0.3.2.RC1
 glob2==0.3
 gunicorn==0.17.4
 lazy==1.1
-lxml==3.0.1
+lxml==3.3.5
 mako==0.9.1
 Markdown==2.2.1
 mongoengine==0.7.10