Fix build on CentOS 6 w/ xmlsec1-1.2.19-3

[jtdoepke]

pkgconfig doesn't parse the XMLSEC_CRYPTO macro value correctly from xmlsec1-1.2.19-3 on CentOS 6: it comes already wrapped in quotes "openssl", then xmlsec_setupinfo.py wraps it again ""openssl"". So the gcc command ends up looking something like this:

gcc -DXMLSEC_CRYPTO=""openssl""  # ... other args ...

Which causes a syntax error when compiling main.c:

    /var/tmp/pip-qg0cd5lq-build/src/main.c: In function ‘PyXmlSec_Init’:
    /var/tmp/pip-qg0cd5lq-build/src/main.c:56: error: expected ‘,’ or ‘;’ before ‘openssl’
    error: command 'gcc' failed with exit status 1

The Changelog for the xmlsec1 RPM suggests there's been some bugs with pkg-config that were fixed in later versions.

2014-05-28 - Simo Sorce <simo@redhat.com> - 1.2.20-2
- Update pkg-config fix patch to apply w/o fuzz

...

2014-05-23 - Simo Sorce <simo@redhat.com> - 1.2.19-6
- Fix incomplete patch

2014-05-23 - Simo Sorce <simo@redhat.com> - 1.2.19-5
- Add patch to deal with different behavior of pkg-config in RHEL6

This change just checks if XMLSEC_CRYPTO is already wrapped in quotes.

[bgaifullin]

Thanks for PR.