don't mess with AP_ENABLE_EXCEPTION_HOOK on trunk

don't mess with AP_ENABLE_EXCEPTION_HOOK on trunk

mpm_common defines it later anyway:

In file included from mod_md.c:25:
In file included from /Users/covener/SRC/httpd-trunk/include/mpm_common.h:40:
In file included from /Users/covener/SRC/httpd-trunk/include/ap_config.h:184:
/Users/covener/SRC/httpd-trunk/include/ap_config_auto.h:11:9: error: 'AP_ENABLE_EXCEPTION_HOOK' macro redefined [-Werror,-Wmacro-redefined]

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1864153 13f79535-47bb-0310-9956-ffa450edef68