Hooks: avoid problems with backslashes in paths

Hooks: avoid problems with backslashes in paths

Calling sh -c with a script path containing backslashes may fail since
the shell may try to process them as escape characters.

Instead of calling

  sh.exe -c 'C:\path\script "$@"' 'C:\path\script' other args

call

  sh.exe -c '$0 "$@"' 'C:\path\script' other args

which avoids this escape processing.

Note that this is not specific to Windows. If the path or the script
name contain backslashes, this also occurs on Unix.

Bug: 558577
Change-Id: I47d63db6f8644f956c55c42b07dbcad7d7f305aa
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>