4.2.0 Compile warnings

[nesterenkodm]

Having deployment target iOS 7.0+;

...Adjust/Adjust/ADJUtil.m:50:10: warning: comparison of address of 'NSURLIsExcludedFromBackupKey' equal to a null pointer is always false [-Wtautological-pointer-compare]
    if (&NSURLIsExcludedFromBackupKey == nil) { // iOS 5.0.1 and lower

...Adjust/Adjust/ADJPackageBuilder.m:222:15: warning: comparison of constant 0 with expression of type 'BOOL' (aka 'bool') is always false [-Wtautological-constant-out-of-range-compare]
    if (value < 0) return;
        ~~~~~ ^ ~

[wellle]

Thanks, we'll check that.

[uerceg]

Closed with PR #98