fix gbs build error

fix gbs build error
https://bugs.tizen.org/browse/DEVT-440
This build error happens in such senario:
1. when there exist two or more same rpm packages with different version,
And this package don't depend on other pcakges.
So During parsing the cache file .srcfiles.cache, according to the rule of expanddeps file,
If there is no "R:" section for this package, it will not compare the version.
the releated variable will always save the first package info.
This error is caused by:
https://review.tizen.org/gerrit/gitweb?p=tools/build.git;a=commit;h=bb2a3cc363850d2751058d34c90d5fe00bc80cbc
Change-Id: I2ecdd621bc0350278158fe92dc715f370aba875f
Signed-off-by: biao716.wang <biao716.wang@samsung.com>