logd: fix write errors in no_epipe test This length needs to contain the length of '\0' when writing string to socket. Bug: 195717127 Test: run CtsLogdTestCases pass Change-Id: Ide95656d012d97511c57a4a7cdabcc12a5c33727 (cherry picked from commit 2bb97ecd62c385465d2375bc62a1675d8c838e35)