[CALCITE-743] Ensure only a single source assembly is executed.
[CALCITE-743] Ensure only a single source assembly is executed.

Since Calcite has its own assembly, we need to disable the Apache Parent POM assembly since they conflicting instructions.

b-slim/calcite,datametica/calcite,adeshr/incubator-calcite,wanglan/calcite,looker-open-source/calcite-avatica,joshelser/incubator-calcite,googleinterns/calcite,YrAuYong/incubator-calcite,minji-kim/calcite,julianhyde/calcite,joshelser/calcite-avatica,joshelser/incubator-calcite,dindin5258/calcite,julianhyde/calcite,sudheeshkatkam/incubator-calcite,julianhyde/calcite,vlsi/calcite,xhoong/incubator-calcite,looker-open-source/calcite-avatica,adeshr/incubator-calcite,apache/calcite,apache/calcite,vlsi/calcite,sudheeshkatkam/incubator-calcite,apache/calcite-avatica,sudheeshkatkam/incubator-calcite,sudheeshkatkam/incubator-calcite,vlsi/calcite,minji-kim/calcite,looker-open-source/calcite,jcamachor/calcite,apache/calcite-avatica,julianhyde/calcite,amoghmargoor/incubator-calcite,datametica/calcite,googleinterns/calcite,looker-open-source/calcite-avatica,looker-open-source/calcite,looker-open-source/calcite,jcamachor/calcite,looker-open-source/calcite-avatica,yeongwei/incubator-calcite,googleinterns/calcite,looker-open-source/calcite,arina-ielchiieva/calcite,b-slim/calcite,julianhyde/calcite,arina-ielchiieva/calcite,b-slim/calcite,arina-ielchiieva/calcite,apache/calcite-avatica,datametica/calcite,adeshr/incubator-calcite,looker-open-source/calcite,googleinterns/calcite,dindin5258/calcite,sreev/incubator-calcite,yeongwei/incubator-calcite,apache/calcite,sreev/incubator-calcite,jcamachor/calcite,hsuanyi/incubator-calcite,minji-kim/calcite,vlsi/incubator-calcite,wanglan/calcite,YrAuYong/incubator-calcite,minji-kim/calcite,datametica/calcite,xhoong/incubator-calcite,joshelser/incubator-calcite,arina-ielchiieva/calcite,datametica/calcite,amoghmargoor/incubator-calcite,amoghmargoor/incubator-calcite,apache/calcite,arina-ielchiieva/calcite,wanglan/calcite,apache/calcite-avatica,looker-open-source/calcite,jcamachor/calcite,apache/calcite,hsuanyi/incubator-calcite,hsuanyi/incubator-calcite,vlsi/calcite,googleinterns/calcite,googleinterns/calcite,vlsi/incubator-calcite,YrAuYong/incubator-calcite,hsuanyi/incubator-calcite,wanglan/calcite,adeshr/incubator-calcite,dindin5258/calcite,minji-kim/calcite,yeongwei/incubator-calcite,sreev/incubator-calcite,vlsi/calcite,yeongwei/incubator-calcite,dindin5258/calcite,sreev/incubator-calcite,apache/calcite-avatica,datametica/calcite,joshelser/calcite-avatica,dindin5258/calcite,jcamachor/calcite,julianhyde/calcite,b-slim/calcite,b-slim/calcite,jcamachor/calcite,dindin5258/calcite,looker-open-source/calcite-avatica,xhoong/incubator-calcite,apache/calcite,joshelser/calcite-avatica,YrAuYong/incubator-calcite,vlsi/calcite,xhoong/incubator-calcite,amoghmargoor/incubator-calcite,joshelser/incubator-calcite