calculateCallability fails when none pass: ValueError: could not convert string to float

[f73chen]

Problem: When PASS= , the WDL crashes because it tries to cast an empty line to float
PASS="$(bedtools intersect -a normal.callable -b tumor.callable -wao | awk '{sum+=$9} END{print sum}')"

pass_count = int(float("${PASS}"))

Solution: Replace PASS with this line instead so it starts at 0:
PASS="$(bedtools intersect -a normal.callable -b tumor.callable -wao | awk 'BEGIN{sum=0} {sum+=$9} END{print sum}')"