Add --with-kvm-path configure option

This allows to configure a different path to the kvm binary. By default
/usr/bin/kvm is used, which is the one found in debian and ubuntu.

Reviewed-by: imsnah

Makefile.am

@@ -260,6 +260,7 @@ lib/_autoconf.py: Makefile stamp-directories
 	  echo "XEN_INITRD = '$(XEN_INITRD)'"; \
 	  echo "FILE_STORAGE_DIR = '$(FILE_STORAGE_DIR)'"; \
 	  echo "IALLOCATOR_SEARCH_PATH = [$(IALLOCATOR_SEARCH_PATH)]"; \
+	  echo "KVM_PATH = '$(KVM_PATH)'"; \
 	} > $@
 
 $(REPLACE_VARS_SED): Makefile stamp-directories

configure.ac

@@ -89,6 +89,16 @@ AC_ARG_WITH([file-storage-dir],
   [file_storage_dir="/srv/ganeti/file-storage"])
 AC_SUBST(FILE_STORAGE_DIR, $file_storage_dir)
 
+# --with-kvm-path=...
+AC_ARG_WITH([kvm-path],
+  [AS_HELP_STRING([--with-kvm-path=PATH],
+    [absolute path to the kvm binary]
+    [ (default is /usr/bin/kvm)]
+  )],
+  [kvm_path="$withval"],
+  [kvm_path="/usr/bin/kvm"])
+AC_SUBST(KVM_PATH, $kvm_path)
+
 # Check common programs
 AC_PROG_INSTALL
 AC_PROG_LN_S

lib/constants.py

@@ -126,6 +126,8 @@ EXPORT_CONF_FILE = "config.ini"
 XEN_KERNEL = _autoconf.XEN_KERNEL
 XEN_INITRD = _autoconf.XEN_INITRD
 
+KVM_PATH = _autoconf.KVM_PATH
+
 VALUE_DEFAULT = "default"
 VALUE_NONE = "none"