Fix No updates found for users with Turkish Locale

There is a problem with Java's toLowerCase() method which returns
"LATIN SMALL LETTER DOTLESS I" for "I" character. This breaks update check
because Utils.getInstalledBuildType() returns "nıghtly (notice dottles small
i)" instead of "nightly".

This change forces toLowerCase() to use ROOT locale which is recommended in
javadocs

There is a note for Turkish locale on javadocs:
http://devdocs.io/openjdk~8/java/lang/string#toLowerCase--



Change-Id: Ifada815202588d67643136846de08f94cefb46a5
Signed-off-by: Mustafa Karatas <mstfkaratas@gmail.com>