secril-client: return exact error code from blockingWrite()

Change-Id: Ibb6d3636648480c53a2fd19044eefe5b97f1eceb
diff --git a/ril/libsecril-client/secril-client.cpp b/ril/libsecril-client/secril-client.cpp
index 3277b1d..d96f19b 100755
--- a/ril/libsecril-client/secril-client.cpp
+++ b/ril/libsecril-client/secril-client.cpp
@@ -1572,9 +1572,8 @@
         }
         else {
             RLOGE ("RIL Response: unexpected error on write errno:%d", errno);
-            printf("RIL Response: unexpected error on write errno:%d\n", errno);
             close(fd);
-            return -1;
+            return -errno;
         }
     }