adb: clean up 0 --> NULL for pointers

Change-Id: I9216fdf534d807a55dfbc6800b5c3ef5f8c83368
diff --git a/adb/sockets.c b/adb/sockets.c
index 9f1b598..58dcfbb 100644
--- a/adb/sockets.c
+++ b/adb/sockets.c
@@ -366,7 +366,7 @@
 asocket *create_local_socket(int fd)
 {
     asocket *s = calloc(1, sizeof(asocket));
-    if(s == 0) fatal("cannot allocate socket");
+    if (s == NULL) fatal("cannot allocate socket");
     install_local_socket(s);
     s->fd = fd;
     s->enqueue = local_socket_enqueue;
@@ -482,7 +482,7 @@
     asocket *s = calloc(1, sizeof(aremotesocket));
     adisconnect*  dis = &((aremotesocket*)s)->disconnect;
 
-    if(s == 0) fatal("cannot allocate socket");
+    if (s == NULL) fatal("cannot allocate socket");
     s->id = id;
     s->enqueue = remote_socket_enqueue;
     s->ready = remote_socket_ready;
@@ -761,7 +761,7 @@
 {
     D("Creating smart socket \n");
     asocket *s = calloc(1, sizeof(asocket));
-    if(s == 0) fatal("cannot allocate socket");
+    if (s == NULL) fatal("cannot allocate socket");
     s->id = 0;
     s->enqueue = smart_socket_enqueue;
     s->ready = smart_socket_ready;