CA-35383: if the tools filename build number has a non-digit suffix, disregard it.
CA-35383: if the tools filename build number has a non-digit suffix, disregard it.

XCP hosts currently have tools isos in
  /opt/xensource/packages/iso/xs-tools-<version>-<build><suffix>.iso
where <build> is an integer and <suffix> is a string.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

sharady/xcp-networkd,koushikcgit/xcp-rrdd,djs55/xcp-networkd,djs55/xcp-networkd,djs55/xcp-rrdd,koushikcgit/xcp-rrdd,simonjbeaumont/xcp-rrdd,johnelse/xcp-rrdd,djs55/squeezed,sharady/xcp-networkd,koushikcgit/xcp-networkd,koushikcgit/xcp-rrdd,robhoes/squeezed,koushikcgit/xcp-networkd,djs55/xcp-rrdd,johnelse/xcp-rrdd,simonjbeaumont/xcp-rrdd