package_manager.py: search provides when not found by pkgname

package_manager.py: search provides when not found by pkgname

Fixed when:
PACKAGE_CLASSES = "package_rpm"
IMAGE_INSTALL_append = " perl-module-warnings-register"

$ bitbake core-image-minimal
[snip]
ERROR: perl-module-warnings-register not found in the base feeds
[snip]

And it works well when PACKAGE_CLASSES = "package_ipk" since perl
provides perl-module-warnings-register, the "smart install
perl-module-warnings-register" also works well, this was because
_search_pkg_name_in_feeds() only searched pkg name, but no provides,
this patch fixes the problem.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>