Remove dynamically-loaded use of DNS lookup feature for INTEGRITY.

Static libnet is enough for DNS resolution.
This commit specializes the removal of dynamic DNS library load, but
this should probably also be done when using a static build.

Change-Id: I597bdd528649849844a0ee46d0706f22d6f595d4
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

src/network/kernel/kernel.pri

@@ -26,7 +26,10 @@ SOURCES += kernel/qauthenticator.cpp \
            kernel/qnetworkproxy.cpp \
 	   kernel/qnetworkinterface.cpp
 
-unix:SOURCES += kernel/qdnslookup_unix.cpp kernel/qhostinfo_unix.cpp kernel/qnetworkinterface_unix.cpp
+unix {
+    !integrity: SOURCES += kernel/qdnslookup_unix.cpp
+    SOURCES += kernel/qhostinfo_unix.cpp kernel/qnetworkinterface_unix.cpp
+}
 
 android {
     SOURCES -= kernel/qdnslookup_unix.cpp
@@ -47,7 +50,6 @@ win32: {
                    kernel/qnetworkinterface_winrt.cpp
     }
 }
-integrity:SOURCES += kernel/qdnslookup_unix.cpp kernel/qhostinfo_unix.cpp kernel/qnetworkinterface_unix.cpp
 
 mac {
     LIBS_PRIVATE += -framework SystemConfiguration -framework CoreFoundation