Move BACKTRACE_NO_TID to BACKTRACE_CURRENT_THREAD.

Use a bit better name for this. The other name was a bit confusing.

Change-Id: I1261f2ee3854a9c8b82133ad0bfbbbe48b43c9ac
diff --git a/include/utils/CallStack.h b/include/utils/CallStack.h
index 5836037..bfe2ddb 100644
--- a/include/utils/CallStack.h
+++ b/include/utils/CallStack.h
@@ -44,7 +44,7 @@
 
     // Immediately collect the stack traces for the specified thread.
     // The default is to dump the stack of the current call.
-    void update(int32_t ignoreDepth=1, pid_t tid=BACKTRACE_NO_TID);
+    void update(int32_t ignoreDepth=1, pid_t tid=BACKTRACE_CURRENT_THREAD);
 
     // Dump a stack trace to the log using the supplied logtag.
     void log(const char* logtag,