Convert to new override syntax

This is the result of automated script conversion:

scripts/contrib/convert-overrides.py <oe-core directory>

converting the metadata to use ":" as the override character instead of "_".

(From OE-Core rev: 42344347be29f0997cc2f7636d9603b1fe1875ae)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python-testtools.inc

@@ -17,7 +17,7 @@ DEPENDS += " \
     ${PYTHON_PN}-pbr-native \
     "
 
-RDEPENDS_${PN} += "\
+RDEPENDS:${PN} += "\
     ${PYTHON_PN}-doctest \
     ${PYTHON_PN}-extras \
     ${PYTHON_PN}-pbr \