[OPENMP] Rename OMPCapturedFieldDecl to OMPCapturedExprDecl, NFC.
OMPCapturedExprDecl allows caopturing not only of fielddecls, but also
other expressions. It also allows to simplify codegen for several
clauses.

llvm-svn: 260492
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index b699bec..58c3cc3 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -655,7 +655,7 @@
     case ObjCCategoryImpl:
     case Import:
     case OMPThreadPrivate:
-    case OMPCapturedField:
+    case OMPCapturedExpr:
     case Empty:
       // Never looked up by name.
       return 0;