python: Use hardcoded python path in libvirt.py

This partially reverts (and fixes that part in a different way) commit
e4384459c93e3e786aa483c7f077d1d22148f689, which replaced
``/usr/bin/python'' with ``/usr/bin/env python'' in all examples or
scripts used during build to generate other files.

However, python bindings module is compiled and linked against a
specific python discovered or explicitly provided in configure phase.
Thus libvirt.py, which is generated and installed into the system,
should use the same python binary for which the module has been built.

The hunk in Makefile.am replaces $(srcdir) with $(PYTHON), which might
seem wrong but it is not. generator.py didn't use any of its command
line arguments so passing $(srcdir) to it was redundant.

python/Makefile.am

@@ -53,7 +53,7 @@ GENERATED= libvirt-export.c \
 	   libvirt.py
 
 generated.stamp: $(srcdir)/$(GENERATE) $(API_DESC)
-	$(PYTHON) $(srcdir)/$(GENERATE) $(srcdir)
+	$(PYTHON) $(srcdir)/$(GENERATE) $(PYTHON)
 	touch $@
 
 $(GENERATED): generated.stamp

python/generator.py

@@ -14,6 +14,11 @@ import re
 if __name__ == "__main__":
     # launched as a script
     srcPref = os.path.dirname(sys.argv[0])
+    if len(sys.argv) > 1:
+        python = sys.argv[1]
+    else:
+        print "Python binary not specified"
+        sys.exit(1)
 else:
     # imported
     srcPref = os.path.dirname(__file__)
@@ -1012,7 +1017,7 @@ def buildWrappers():
     classes = open("libvirt.py", "w")
 
     extra = open(os.path.join(srcPref,"libvirt-override.py"), "r")
-    classes.write("#!/usr/bin/env python\n")
+    classes.write("#! " + python + " -i\n")
     classes.write("#\n")
     classes.write("# WARNING WARNING WARNING WARNING\n")
     classes.write("#\n")

python/libvirt-override.py

@@ -2,11 +2,6 @@
 # Manually written part of python bindings for libvirt
 #
 
-# Specify -i commandline option after python was started
-if __name__ == "__main__":
-    import os
-    os.environ["PYTHONINSPECT"] = "1"
-
 # On cygwin, the DLL is called cygvirtmod.dll
 try:
     import libvirtmod