fvtr: fix package-check execution on cross
fvtr: fix package-check execution on cross

Fix 2 issues:
 - The separator between the package name and version in a deb package
   is '_' instead of '-'.  Make the cross-common distro-agnostic.
 - There is a package whose flavor doesn't have a second, i.e. just
   'cross'.  This package needs its own regular expression.

Fixes issue #134.

Signed-off-by: Tulio Magno Quites Machado Filho <0e1b3d0765ee75ed64fa2e34822e4949a70a1429@linux.vnet.ibm.com>

advancetoolchain/advance-toolchain,advancetoolchain/advance-toolchain,rzinsly/advance-toolchain,advancetoolchain/advance-toolchain,rzinsly/advance-toolchain,advancetoolchain/advance-toolchain,rzinsly/advance-toolchain,advancetoolchain/advance-toolchain,rzinsly/advance-toolchain,advancetoolchain/advance-toolchain,rzinsly/advance-toolchain,rzinsly/advance-toolchain