rpc: avoid freeing uninitialized variable

Detected by Coverity.  Both are instances of bad things happening
if pipe2 fails; the virNetClientNew failure could free garbage,
and virNetSocketNewConnectCommand could close random fds.

Note: POSIX doesn't guarantee the contents of fd[0] and fd[1]
after pipe failure: http://austingroupbugs.net/view.php?id=467
We may need to introduce a virPipe2 wrapper that guarantees
that on pipe failure, the fds are explicitly set to -1, rather
than our current state of assuming the fds are unchanged from
their value prior to the failed pipe call.

* src/rpc/virnetclient.c (virNetClientNew): Initialize variable.
* src/rpc/virnetsocket.c (virNetSocketNewConnectCommand):
Likewise.

src/rpc/virnetclient.c

@@ -113,7 +113,7 @@ static void virNetClientIncomingEvent(virNetSocketPtr sock,
 static virNetClientPtr virNetClientNew(virNetSocketPtr sock,
                                        const char *hostname)
 {
-    virNetClientPtr client;
+    virNetClientPtr client = NULL;
     int wakeupFD[2] = { -1, -1 };
 
     if (pipe2(wakeupFD, O_CLOEXEC) < 0) {

src/rpc/virnetsocket.c

@@ -511,8 +511,8 @@ int virNetSocketNewConnectCommand(virCommandPtr cmd,
                                   virNetSocketPtr *retsock)
 {
     pid_t pid = 0;
-    int sv[2];
-    int errfd[2];
+    int sv[2] = { -1, -1 };
+    int errfd[2] = { -1, -1 };
 
     *retsock = NULL;