python2: Fix disabling module bsddb

Using this minimal defconfig

BR2_TOOLCHAIN_EXTERNAL=y
BR2_PACKAGE_PYTHON=y
BR2_PACKAGE_BERKELEYDB=y

the current code does not prevent the build of

output/build/python-2.7.6/Modules/_bsddb.o

because the module is really called _bsddb,
see python-2.7.6/Modules/_bsddb.c, line 9604.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/python/python-110-optional-db.patch

@@ -70,7 +70,7 @@ Index: b/configure.ac
 +	AS_HELP_STRING([--disable-bsddb], [disable BerkeyleyDB]),
 +	[ if test "$enableval" = "no"; then
 +    	     BSDDB=no
-+    	     DISABLED_EXTENSIONS="${DISABLED_EXTENSIONS} bsddb"
++    	     DISABLED_EXTENSIONS="${DISABLED_EXTENSIONS} _bsddb"
 +  	  else
 +	     BSDDB=yes
 +  	  fi], [ BSDDB=yes ])