Avoid confusing "read prevented write" log messages.

Moving to a "function: message" style avoids ambiguity.

Change-Id: If9d590e50265c61725d3673bd03796e65edd2d5e
diff --git a/libc/bionic/__strchr_chk.cpp b/libc/bionic/__strchr_chk.cpp
index 51d35d0..03b6b30 100644
--- a/libc/bionic/__strchr_chk.cpp
+++ b/libc/bionic/__strchr_chk.cpp
@@ -33,7 +33,7 @@
 extern "C" char* __strchr_chk(const char* p, int ch, size_t s_len) {
   for (;; ++p, s_len--) {
     if (__predict_false(s_len == 0)) {
-      __fortify_chk_fail("strchr prevented read past end of buffer", 0);
+      __fortify_chk_fail("strchr: prevented read past end of buffer", 0);
     }
     if (*p == static_cast<char>(ch)) {
       return const_cast<char*>(p);