checkapk: hotfix for incorrect rebuild recommends if file name changed
As pointed out by @kdaudt, checkapk would recommend aport rebuilds if the file name changed without a change in the SONAME. This commit attempts to workaround this by sorting the file output and processing .so files as pairs of two (previous .so, new .so). For both files, the SONAME is extracted using scanelf(1) and then compared for equality. If the SONAME is not equal, rebuilds are recommended.