pt-summary for 2.1, also changes to pt-mysql-summary from Daniel's review

t/lib/bash/summary_common.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+plan 3
+
+TMPDIR="$TEST_TMPDIR"
+PATH="$PATH:$PERCONA_TOOLKIT_SANDBOX/bin"
+
+. "$LIB_DIR/summary_common.sh"
+
+p="$TMPDIR/get_var_samples"
+
+echo "test1    abcdef" > "$p"
+is \
+   "$(get_var test1 "$p")" \
+   "abcdef"                \
+   "Sanity check, get_var works"
+
+echo "test2    abc def" > "$p"
+is \
+   "$(get_var test2 "$p")" \
+   "abc def"                \
+   "get_var works even if the value has spaces"
+
+echo "test::1    abcdef" > "$p"
+is \
+   "$(get_var "test::1" "$p")" \
+   "abcdef"                \
+   "get_var works if the 'key' has colons"
+