cleanup unnecessary path from configuration file

Author: Daniel Kroening

buildspec-windows.yml

@@ -11,7 +11,7 @@ phases:
     commands:
       - |
         $env:Path = "C:\tools\cygwin\bin;$env:Path"
-        C:\tools\cygwin\bin\bash -c "make -C src minisat2-download DOWNLOADER=wget"
+        bash -c "make -C src minisat2-download DOWNLOADER=wget"
 
       - |
         $env:Path = "C:\tools\cygwin\bin;c:\tools\clcache\clcache-4.1.0;$env:Path"