Fix the text of the error message, in the case of service specific error

This is a followup CL to address the last code review comment at:
aosp/1612458.

Test: N/A. This is only a change in the text of the error.

Change-Id: I5d5a040ee23ef20836633e296376c6e4bbfc0e47
diff --git a/identity/Credential.cpp b/identity/Credential.cpp
index 183ddeb..23e144f 100644
--- a/identity/Credential.cpp
+++ b/identity/Credential.cpp
@@ -286,8 +286,8 @@
                 LOG(ERROR) << "Error getting tokens from keystore2: " << result.getDescription();
                 return false;
             } else {
-                // Log the reason for not finding auth tokens.
-                LOG(INFO) << "Auth tokens not found: " << result.getDescription();
+                // Log the reason for not receiving auth tokens from keystore2.
+                LOG(INFO) << "Auth tokens were not received due to: " << result.getDescription();
             }
         }
         return true;