Add missing lock in SocketListener.

Change-Id: I3d97a06381fce67ef13b1ccdeaa4e8e2830ab2aa
diff --git a/libsysutils/src/SocketListener.cpp b/libsysutils/src/SocketListener.cpp
index 7af221f..1bc06db 100644
--- a/libsysutils/src/SocketListener.cpp
+++ b/libsysutils/src/SocketListener.cpp
@@ -198,6 +198,7 @@
                         pthread_mutex_unlock(&mClientsLock);
                     }
                     FD_CLR(fd, &read_fds);
+                    pthread_mutex_lock(&mClientsLock);
                     continue;
                 }
             }