Merge pull request #11076 from dgquintas/epoll_error_static_string

Don't crate GRPC_OS_ERROR with a non-static string
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.c
index 5f2c989..685581b 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.c
@@ -769,7 +769,7 @@
               GRPC_ERROR_INT_ERRNO, err),
           GRPC_ERROR_STR_OS_ERROR,
           grpc_slice_from_static_string(strerror(err))),
-      GRPC_ERROR_STR_SYSCALL, grpc_slice_from_static_string(call_name));
+      GRPC_ERROR_STR_SYSCALL, grpc_slice_from_copied_string(call_name));
 }
 
 #ifdef GPR_WINDOWS