Recommit of r263252, [ELF] - Change all messages to lowercase to be consistent.

which was reverted because included
unrelative changes by mistake.

Original commit message:

[ELF] - Change all messages to lowercase to be consistent.

That is directly opposite to http://reviews.llvm.org/D18045,
which was reverted.

This patch changes all messages to start from lowercase letter if
they were not before.

That is done to be consistent with clang.

Differential revision: http://reviews.llvm.org/D18085

llvm-svn: 263337
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index 30179e4..aea97c4 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -73,12 +73,12 @@
   case SymbolBody::UndefinedKind:
     return 0;
   case SymbolBody::LazyKind:
-    assert(Body.isUsedInRegularObj() && "Lazy symbol reached writer");
+    assert(Body.isUsedInRegularObj() && "lazy symbol reached writer");
     return 0;
   case SymbolBody::DefinedBitcodeKind:
-    llvm_unreachable("Should have been replaced");
+    llvm_unreachable("should have been replaced");
   }
-  llvm_unreachable("Invalid symbol kind");
+  llvm_unreachable("invalid symbol kind");
 }
 
 template <class ELFT>