error: Remove NULL checks on error_propagate() calls

Patch created mechanically by rerunning:

  $  spatch --sp-file scripts/coccinelle/error_propagate_null.cocci \
            --macro-file scripts/cocci-macro-file.h \
            --dir . --in-place

Whitespace tidied up manually.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NLaurent Vivier <laurent@vivier.eu>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20181213173113.11211-1-armbru@redhat.com>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

blockdev.c

@@ -992,9 +992,7 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type,
     blk = blockdev_init(filename, bs_opts, &local_err);
     bs_opts = NULL;
     if (!blk) {
-        if (local_err) {
-            error_propagate(errp, local_err);
-        }
+        error_propagate(errp, local_err);
         goto fail;
     } else {
         assert(!local_err);

hw/s390x/s390-pci-bus.c

@@ -731,9 +731,7 @@ static void s390_pcihost_realize(DeviceState *dev, Error **errp)
 
     css_register_io_adapters(CSS_IO_ADAPTER_PCI, true, false,
                              S390_ADAPTER_SUPPRESSIBLE, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-    }
+    error_propagate(errp, local_err);
 }
 
 static int s390_pci_msix_init(S390PCIBusDevice *pbdev)

qga/commands-posix.c

@@ -1573,10 +1573,7 @@ static bool systemd_supports_mode(SuspendMode mode, Error **errp)
         return true;
     }
 
-    if (local_err) {
-        error_propagate(errp, local_err);
-    }
-
+    error_propagate(errp, local_err);
     return false;
 }
 
@@ -1782,7 +1779,7 @@ static void guest_suspend(SuspendMode mode, Error **errp)
     if (!mode_supported) {
         error_setg(errp,
                    "the requested suspend mode is not supported by the guest");
-    } else if (local_err) {
+    } else {
         error_propagate(errp, local_err);
     }
 }