bug#6784: 24.0.50; cmdproxy incosistency with command pathnames

["Óscar Fuentes" <ofv@wanadoo.es>]

A command path name that contains slashes (instead of backslashes) will
work fine with cmdproxy as far as it doesn't require to be executed
through a shell. Otherwise only backslashes work. Example:

cmdproxy.exe -c "c:/foo/bar.exe"

which executes bar.exe through CreateProces, works fine, but

cmdproxy.exe -c "c:/foo/bar.exe | zoo.exe"

which invokes the shell for executing the command, fails with an error
message that comes from cmd.exe and that says "c:" is not recognized as
a command.

OTOH,

cmdproxy.exe -c "c:\foo\bar.exe | zoo.exe"

works fine.

cmd.exe has no problem with commands that uses the slash as directory
separator, as this works OK:

cmd /c c:/foo/bar.exe

so the problem must be in cmdproxy, which probably splits the command as

"c:" "/foo/bar.exe"

and passes it as separate arguments to the shell.

Although this bug possibly is not hard to fix, maybe we should consider
the larger scenario: is it worth the trouble having two separate
execution paths on cmdproxy? Inconsistencies like this among the two
separate ways of executing commands may arise on the future, confusing
the users. Maybe we should remove the CreateProcess method and do
everything through the underlying shell.