Duplicate apk names on package update.

+minor fixes

Bug: 187710420
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest
Change-Id: Iced479532b38bddcd8655df3ce08611434965cf4
diff --git a/services/incremental/path.cpp b/services/incremental/path.cpp
index bf4e9616..73e00ae 100644
--- a/services/incremental/path.cpp
+++ b/services/incremental/path.cpp
@@ -171,7 +171,9 @@
 }
 
 details::CStrWrapper::CStrWrapper(std::string_view sv) {
-    if (sv[sv.size()] == '\0') {
+    if (!sv.data()) {
+        mCstr = "";
+    } else if (sv[sv.size()] == '\0') {
         mCstr = sv.data();
     } else {
         mCopy.emplace(sv);