crypto/fs_mgr: rename local funtion getline() to fs_getline() to avoid conflicts with global funtion getline() defined in bionic. Only effects device that define TW_INCLUDE_JB_CRYPTO := true in boardconfig.mk

Summary: Devices that require TW_INCLUDE_JB_CRYPTO (HTC 8960's) will fail here for a duplicate funtion definition from bionic. Changing names on TWRP's local getline() funtion similar to what google did here https://android.googlesource.com/platform/system/core/+/657cd83899355c7f488dcd3294a523ec120f840f%5E2..657cd83899355c7f488dcd3294a523ec120f840f/

Test Plan: Required for Evita build, Ensure it doesn't break anythign else and merge

Reviewers: synergy, randall.rushing

Reviewed By: synergy

Differential Revision: http://review.codefirex.com/D383

Change-Id: I52577bdea49953553e469ecfb6970381a58e788f