test: Don't use 'Error:' or 'error:' in test output

This is parsed by msbuild when using Visual Studio project
files, and will automatically fail the build if encountered.
This is a bug (or badly designed intentional behaviour) in
msbuild.  See
  http://blogs.msdn.com/b/dsvc/archive/2012/02/29/output-from-exec-task-resulting-in-build-failure.aspx
for further details.

test/gtx/gtx_integer.cpp

@@ -63,10 +63,10 @@ int test_log2()
 		Error += glm::abs(double(A) - B) <= 24 ? 0 : 1;
 		assert(!Error);
 
-		printf("Log2(%d) Error: %d, %d\n", 1 << i, A, B);
+		printf("Log2(%d) error A=%d, B=%d\n", 1 << i, A, B);
 	}
 
-	printf("log2 error: %d\n", Error);
+	printf("log2 error=%d\n", Error);
 
 	return Error;
 }