qgrep: fix -Wcalloc-transposed-args warning #105

Job	Run time
coverity	36s
valgrind	3m 3s
make-check-ubuntu-x64 (ubuntu-latest, gcc, --enable-qmanifest --enable-qtegrity)	36s
make-check-ubuntu-x64 (ubuntu-latest, gcc, --disable-qmanifest --enable-qtegrity)	37s
make-check-ubuntu-x64 (ubuntu-latest, gcc, --enable-qmanifest --disable-qtegrity)	38s
make-check-ubuntu-x64 (ubuntu-latest, gcc, --disable-qmanifest --disable-qtegrity)	39s
make-check-ubuntu-x64 (ubuntu-latest, gcc)	42s
make-check-ubuntu-x64 (ubuntu-latest, clang, --enable-qmanifest --enable-qtegrity)	48s
make-check-ubuntu-x64 (ubuntu-latest, clang, --disable-qmanifest --enable-qtegrity)	51s
make-check-ubuntu-x64 (ubuntu-latest, clang, --enable-qmanifest --disable-qtegrity)	51s
make-check-ubuntu-x64 (ubuntu-latest, clang, --disable-qmanifest --disable-qtegrity)	1m 1s
make-check-ubuntu-x64 (ubuntu-latest, clang)	49s
	11m 11s

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