skip installing documentation

I got this error on the install step for this distro:

```
created directory `/home/ollisg/.perlbrew/libs/perl-5.18.1@dev/lib/perl5/auto/share/dist/Alien-OpenSSL/ssl/man/man7'
installing man1/CA.pl.1
installing man1/asn1parse.1
installing man1/ca.1
installing man1/ciphers.1
installing man1/cms.1
cms.pod around line 457: Expected text after =item, not a number
cms.pod around line 461: Expected text after =item, not a number
cms.pod around line 465: Expected text after =item, not a number
cms.pod around line 470: Expected text after =item, not a number
cms.pod around line 474: Expected text after =item, not a number
POD document had syntax errors at /home/ollisg/.perlbrew/libs/perl-5.18.1@dev/bin/pod2man line 69.
```

Unfortunately this left the distro half installed.

This patch does an `make install_sw` instead of a `make install`.  I think most people are not going to peruse the documentation from the share directory, but I could be wrong.

A slightly better solution might be to do an optional `make install_doc` (minus the success check) after the `make install_sw`, but I am not sure if there is a good Alien::Base way to do that portably.

I appreciate your consideration of this patch.