installer: work around misquoting in Git Bash Here

When calling `Git Bash Here` from the background of the `C:\` directory
in Windows Explorer, the term `%v` is expanded to the directory. To
allow for spaces in the directory name, we quote that directory when
passing the directory's path as `"--cd=%v"` parameter to `git-bash.exe`.
Unfortunately, the `CommandLineToArgvW()` function mistakes the last
part of `"--cd=C:\"` for a quoted double quote, and as a consequence
`CreateProcess()` fails because there is no `C:"` directory.

To work around this, let's just append `.`: this turns the parameter
into `"--cd=C:\."` which is correctly interpreted as `C:\.` directory.
It works also in the general case, where `%v` does *not* expand into a
path with a trailing backslash because on Windows, `<name>` and
`<name>.` refer to the same file.

This fixes git-for-windows/git#176.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

installer/install.iss.in

@@ -1511,7 +1511,7 @@ begin
         Cmd:='"'+AppDir+'\git-bash.exe" "--cd=%1"';
         if (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\shell\git_shell','',Msg)) or
            (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\shell\git_shell\command','',Cmd)) or
-           (StringChangeEx(Cmd,'%1','%v',false)<>1) or
+           (StringChangeEx(Cmd,'%1','%v.',false)<>1) or
            (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\Background\shell\git_shell','',Msg)) or
            (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\Background\shell\git_shell\command','',Cmd)) then
         begin
@@ -1528,7 +1528,7 @@ begin
         Cmd:='"'+AppDir+'\cmd\git-gui.exe" "--working-dir" "%1"';
         if (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\shell\git_gui','',Msg)) or
            (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\shell\git_gui\command','',Cmd)) or
-           (StringChangeEx(Cmd,'%1','%v',false)<>1) or
+           (StringChangeEx(Cmd,'%1','%v.',false)<>1) or
            (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\Background\shell\git_gui','',Msg)) or
            (not RegWriteStringValue(RootKey,'SOFTWARE\Classes\Directory\Background\shell\git_gui\command','',Cmd))
         then begin