parse_build_log.pl: fixed warning
parse_build_log.pl: fixed warning

Do not use ~= on an uninitialized value.

Change-Id: I21a6e4f3a0b702bc4eb0a1d0ae8d740088834e12
Reviewed-by: Toby Tomkins <23ead35e36f9890dd80f47acf9947179b1bd7fe7@nokia.com>

tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa