Fix #61345: fix install of CGI binary

When CLI was not built but only CGI binary, then a sequence of

$ ./buildconf
$ ./configure  --prefix=/usr/local/phpcgi --disable-cli
$ make -j8
$ sudo rm -rf /usr/local/phpcgi
$ sudo make install

results in the following error:

/bin/bash /srv/smb/php-src.test/libtool --silent --preserve-dup-deps --mode=install cp ext/opcache/opcache.la /srv/smb/php-src.test/modules
Installing shared extensions:     /usr/local/phpcgi/lib/php/extensions/no-debug-non-zts-20121212/
Installing PHP CGI binary:        /usr/local/phpcgi/bin/
cp: cannot create regular file `/usr/local/phpcgi/bin/#INST@28245#': No such file or directory
make: *** [install-cgi] Fehler 1

The solution is to create the binary directory before copying the
CGI binary as e.g. CLI does.

Signed-off-by: Oliver Metz <oliver.metz@gmx.de>

[extensive commit message]

Signed-off-by: Michael Heimpold <mhei@heimpold.de>