Initialize location manager if null when getting last location

[Rkareko]

Add a null check for locationManager when getLastLocation is called.
Initialize locationManager if it is null

[coveralls]

Pull Request Test Coverage Report for Build 1688

• 0 of 7 (0.0%) changed or added relevant lines in 2 files are covered.
• 3135 unchanged lines in 87 files lost coverage.
• Overall coverage decreased (-53.2%) to 0.0%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
library/src/main/java/io/ona/kujaku/location/clients/GoogleLocationClient.java	0	3	0.0%
library/src/main/java/io/ona/kujaku/location/clients/AndroidGpsLocationClient.java	0	4	0.0%

Files with Coverage Reduction	New Missed Lines	%
library/src/main/java/io/ona/kujaku/activities/MapActivity.java	1	0%
library/src/main/java/io/ona/kujaku/listeners/BaseLocationListener.java	1	0%
library/src/main/java/io/ona/kujaku/receivers/KujakuNetworkChangeReceiver.java	1	0%
library/src/main/java/com/mapbox/mapboxsdk/style/layers/ExposedPaintPropertyValue.java	2	0%
library/src/main/java/io/ona/kujaku/exceptions/InvalidArrowLineConfigException.java	2	0%
library/src/main/java/io/ona/kujaku/exceptions/WmtsCapabilitiesException.java	2	0%
library/src/main/java/io/ona/kujaku/utils/NumberFormatter.java	2	0%
library/src/main/java/io/ona/kujaku/wmts/model/WmtsTileMatrixSetLink.java	2	0%
utils/src/main/java/io/ona/kujaku/utils/exceptions/InvalidMapBoxStyleException.java	2	0%
library/src/main/java/io/ona/kujaku/comparisons/EqualToComparison.java	3	0%

Totals
Change from base Build 1677:	-53.2%
Covered Lines:	0
Relevant Lines:	5897

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💛 - Coveralls

[githengi]

We may need to investigate why location manager is getting null. With this fix we don't know which other methods maybe broken because of this.

Either create a method locationManager() that if the references location manager is null reinitializes it so that it can be used in other methods until its known why location manager is becoming null