btrfs-progs: tests: use /bin/bash in the main scripts

Test scripts under tests/ should all use /bin/bash for consistency.

Signed-off-by: David Sterba <dsterba@suse.com>

tests/build-tests.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Usage: $0 [--ccache] [make options]
 #
 # Test various compilation options:

tests/hash-tests.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Test all supported hash algorithms on all backends on the sample test vectors
 # This requires all crypto backends available for full coverage.
 

tests/scan-results.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Look for some frequent error message templates in test logs
 #
 # Usage: $0 [test-log.txt]