Typo fix.

(Thanks to Pieree Moulon for reporting this)

Change-Id: I536724ab4b7e9c97768d5197aa86b41f37a04d38
diff --git a/internal/ceres/problem_impl.cc b/internal/ceres/problem_impl.cc
index 69d672e..f4615f9 100644
--- a/internal/ceres/problem_impl.cc
+++ b/internal/ceres/problem_impl.cc
@@ -84,7 +84,7 @@
       << "Aliasing detected between existing parameter block at memory "
       << "location " << existing_block
       << " and has size " << existing_block_size << " with new parameter "
-      << "block that has memory adderss " << new_block << " and would have "
+      << "block that has memory address " << new_block << " and would have "
       << "size " << new_block_size << ".";
 }