build: fix typo in previous patch

* src/util/virfile.c (safezero_mmap): Fix missing semicolon.
Signed-off-by: NEric Blake <eblake@redhat.com>

src/util/virfile.c

@@ -1119,7 +1119,7 @@ safezero_mmap(int fd ATTRIBUTE_UNUSED,
               off_t offset ATTRIBUTE_UNUSED,
               off_t len ATTRIBUTE_UNUSED)
 {
-    return -1
+    return -1;
 }
 #endif /* !HAVE_MMAP */