Exclude docs/analyzer/ from the default Sphinx build.

This paves the way for converting the analyzer docs to Sphinx (by
setting up a nested Sphinx tree in this directory).

llvm-svn: 171424
diff --git a/clang/docs/conf.py b/clang/docs/conf.py
index b69ccf5..0c35fb1 100644
--- a/clang/docs/conf.py
+++ b/clang/docs/conf.py
@@ -64,7 +64,7 @@
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = ['_build']
+exclude_patterns = ['_build', 'analyzer']
 
 # The reST default role (used for this markup: `text`) to use for all documents.
 #default_role = None