Fix deployment when using build scripts again

Change-Id: If4180b1f79c51bdf38ac99e5eb9acebb3b3342bc
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

shared/shared.pro

-isEmpty(IDE_SOURCE_TREE): IDE_SOURCE_TREE=$$(QTC_SOURCE)
-isEmpty(IDE_SOURCE_TREE): error(Set QTC_SOURCE environment variable)
+isEmpty(IDE_SOURCE_TREE): IDE_SOURCE_TREE = $$(QTC_SOURCE)
+isEmpty(IDE_BUILD_TREE): IDE_BUILD_TREE = $$(QTC_BUILD)
+isEmpty(IDE_SOURCE_TREE): error("Set QTC_SOURCE environment variable")
+isEmpty(IDE_BUILD_TREE): error("Set QTC_BUILD environment variable")
 
 TEMPLATE = aux