[XRay][compiler-rt][NFC] Turn ProudCase functions to humbleCase functions

Summary:
As pointed out in casual reading of the XRay codebase, that we had
some interesting named functions that didn't quite follow the LLVM coding
conventions.

Reviewers: chandlerc, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29625

llvm-svn: 294373
diff --git a/compiler-rt/lib/xray/xray_utils.h b/compiler-rt/lib/xray/xray_utils.h
index d165e84..a78e12a 100644
--- a/compiler-rt/lib/xray/xray_utils.h
+++ b/compiler-rt/lib/xray/xray_utils.h
@@ -21,7 +21,7 @@
 namespace __xray {
 
 // Default implementation of the reporting interface for sanitizer errors.
-void PrintToStdErr(const char *Buffer);
+void printToStdErr(const char *Buffer);
 
 // EINTR-safe write routine, provided a file descriptor and a character range.
 void retryingWriteAll(int Fd, char *Begin, char *End);