initscripts fkt: readhash should only parse lines with a =

A line without a = is clearly invalid.

Signed-off-by: Jonatan Schlag <jonatan.schlag@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/initscripts/system/functions

@@ -910,6 +910,12 @@ readhash() {
 			continue
 		fi
 
+		# Skip lines without a =
+		if ! [[ ${line} =~ [^=]*=[^=]*$ ]]; then
+			echo "Invalid line '${line}'" >&2
+			continue
+		fi
+
 		local key="${line%=*}"
 		local val="${line#*=}"