Rename struct __res_params to res_params

The double-underscore prefixes are a leftover from when this code lived
in bionic. Now we're slowly getting rid of them...

Also cleanup transitive includes a bit.

Test: atest resolv_integration_test resolv_unit_test
Change-Id: I65ed8aed273be4af37a982a167f364a1f33f9a36
diff --git a/server/ResolverController.h b/server/ResolverController.h
index 6d8b741..3cb841c 100644
--- a/server/ResolverController.h
+++ b/server/ResolverController.h
@@ -23,7 +23,7 @@
 #include "Dns64Configuration.h"
 #include "netdutils/InternetAddresses.h"
 
-struct __res_params;
+struct res_params;
 
 namespace android {
 namespace net {
@@ -41,12 +41,12 @@
 
     // TODO: delete this function
     int setDnsServers(unsigned netId, const char* searchDomains, const char** servers,
-            int numservers, const __res_params* params);
+                      int numservers, const res_params* params);
 
     int clearDnsServers(unsigned netid);
 
     int getDnsInfo(unsigned netId, std::vector<std::string>* servers,
-                   std::vector<std::string>* domains, __res_params* params,
+                   std::vector<std::string>* domains, res_params* params,
                    std::vector<android::net::ResolverStats>* stats,
                    std::vector<int32_t>* wait_for_pending_req_timeout_count);