of namespaces (only in the modules where they've
been found) for entities inside those namespaces.

For each NamespaceDecl that has been imported into
the parser, we maintain a map containing
[ModuleSP, ClangNamespaceDecl] pairs in the ASTImporter.
This map has one entry for each module in which the
namespace has been found.  When we later scan for an
entity inside a namespace, we search only the modules
in which that namespace was found.

Also made a small whitespace fix in 
ClangExpressionParser.cpp.

llvm-svn: 141748