lang/php* incorectly deletes extensions from extensions.ini file

[Rolandas Naujikas]

php5-simplexml extension registration has been removed, when package php5-xml 
was removed because

@unexec grep -v xml\.so %D/etc/php/extensions.ini.orig > 
%D/etc/php/extensions.ini || true

Should be better

@unexec grep -v extension=xml\.so %D/etc/php/extensions.ini.orig > 
%D/etc/php/extensions.ini || true

And even add -x to grep to match entire line

Rolandas Naujikas