recognize -install-dir to install to the right directory after admin re-launch (fixes #2626)

Author: kjk

src/Flags.cpp

@@ -230,6 +230,7 @@ static void ParseScrollValue(Point* scroll, const WCHAR* txt) {
     V(ExtractText, "extract-text")               \
     V(Bench, "bench")                            \
     V(Dir, "d")                                  \
+    V(InstallDir, "install-dir")                 \
     V(Lang, "lang")                              \
     V(UpdateSelfTo, "update-self-to")            \
     V(ArgDeleteFile, "delete-file")              \
@@ -538,7 +539,7 @@ void ParseFlags(const WCHAR* cmdLine, Flags& i) {
             i.exitImmediately = true;
             continue;
         }
-        if (arg == Arg::Dir) {
+        if (arg == Arg::Dir || arg == Arg::InstallDir) {
             i.installDir = str::Dup(param);
             continue;
         }

src/Installer.cpp

@@ -219,7 +219,7 @@ static void RemoveShortcutFile(int csidl) {
         return;
     }
     DeleteFileW(path);
-    logf("RemoveShorcuts: deleted '%s'\n", path);
+    logf(L"RemoveShortcutFile: deleted '%s'\n", path);
 }
 
 // those are shortcuts created by versions before 3.4
@@ -1052,7 +1052,8 @@ int RunInstaller() {
     const char* installerLogPath = nullptr;
     if (gCli->log) {
         installerLogPath = GetInstallerLogPath();
-        StartLogToFile(installerLogPath, true);
+        bool removeLog = !gCli->runInstallNow;
+        StartLogToFile(installerLogPath, removeLog);
     }
     logf("------------- Starting SumatraPDF installation\n");