Use unzip from setuphelpers instead of 7z.exe

WAPT/control

@@ -1,11 +1,11 @@
 package           : fws-openssh
-version           : 7.7.2.0-3
+version           : 7.7.2.0-4
 architecture      : all
 section           : base
 priority          : optional
 maintainer        : Daniel Berteaud <daniel@firewall-services.com>
 description       : OpenSSH for Windows
-depends           : fws-7zip
+depends           : 
 conflicts         : 
 maturity          : DEV
 locale            : 

setup.py

@@ -11,7 +11,7 @@ def install():
     run_notfatal(r'sc stop sshd')
     killalltasks('sshd.exe')
     print('    Extract OpenSSH archive')
-    run('"%s" e -y -o"%s" OpenSSH-Win%s.zip' % (makepath(programfiles,'7-Zip','7z.exe'),makepath(programfiles,'OpenSSH'),'64' if iswin64() else '32'))
+    unzip('OpenSSH-Win%s.zip' % '64' if iswin64() else '32',makepath(programfiles,'OpenSSH'))
     print('    Installing the service')
     run(r'powershell.exe -ExecutionPolicy Bypass -File "%s\install-sshd.ps1"' % makepath(programfiles,'OpenSSH'))
     print('    Opening port 22 in the firewall')