hplip: Add python to rdeps

Fixes
ERROR: QA Issue: /usr/share/hplip/upgrade.py contained in package hplip requires /usr/bin/python, but no providers found in RDEPENDS_hplip? [file-rdeps]

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-extended/hplip/hplip_3.12.6.bb

@@ -41,6 +41,7 @@ EXTRA_OECONF += "\
 PACKAGES += "${PN}-ppd ${PN}-cups ${PN}-backend ${PN}-filter ${PN}-hal"
 
 RDEPENDS_${PN} += " \
+        python \
         python-syslog \
         python-pprint \
         python-compression \