adb: don't try to resolve 'localhost'

Misconfigured systems can have localhost pointing to an address that
isn't 127.0.0.1 or ::1.

adb is the only caller of the libcutils socket_loopback functions, so
move them into adb and switch the implementations over to using
INADDR_LOOPBACK and in6addr_loopback, instead of resolving 'localhost'
when connecting.

Bug: http://b/37282612
Test: `killall adb; adb shell`
Test: `killall adb; ip addr del 127.0.0.1/8 dev lo; adb shell`
Change-Id: I01c1885f1d9757ad0f7b353dd04b4d1f057741c8
diff --git a/adb/sysdeps.h b/adb/sysdeps.h
index f95a855..5cd0cd1 100644
--- a/adb/sysdeps.h
+++ b/adb/sysdeps.h
@@ -35,6 +35,7 @@
 #include <android-base/utf8.h>
 
 #include "sysdeps/errno.h"
+#include "sysdeps/network.h"
 #include "sysdeps/stat.h"
 
 /*
@@ -248,8 +249,6 @@
 int unix_isatty(int fd);
 #define  isatty  ___xxx_isatty
 
-int network_loopback_client(int port, int type, std::string* error);
-int network_loopback_server(int port, int type, std::string* error);
 int network_inaddr_any_server(int port, int type, std::string* error);
 
 inline int network_local_client(const char* name, int namespace_id, int type, std::string* error) {
@@ -587,17 +586,6 @@
   return fd;
 }
 
-inline int network_loopback_client(int port, int type, std::string* error) {
-  return _fd_set_error_str(socket_network_client("localhost", port, type), error);
-}
-
-inline int network_loopback_server(int port, int type, std::string* error) {
-  int fd = socket_loopback_server(port, type);
-  if (fd < 0 && errno == EAFNOSUPPORT)
-      return _fd_set_error_str(socket_loopback_server6(port, type), error);
-  return _fd_set_error_str(fd, error);
-}
-
 inline int network_inaddr_any_server(int port, int type, std::string* error) {
   return _fd_set_error_str(socket_inaddr_any_server(port, type), error);
 }