[BUG] The CentOS package libpng-development doesn't install

The external test dependencies for CentOS specify libpng-dev as the package name for libpng-development. The correct name for that package on CentOS is libpng-devel.
In the file pts-core/external-test-dependencies/xml/centos-packages.xml, this bit

Code:

---

                <Package>
                        <GenericName>libpng-development</GenericName>
                        <PackageName>libpng-dev</PackageName>
                        <FileCheck>/usr/include/libpng12/png.h</FileCheck>
                </Package>

---

should be

Code:

---

                <Package>
                        <GenericName>libpng-development</GenericName>
                        <PackageName>libpng-devel</PackageName>
                        <FileCheck>/usr/include/libpng12/png.h</FileCheck>
                </Package>

---