vsicurl.py: make it work with a curl version with a rc suffix

Author: rouault

autotest/gcore/vsicurl.py

@@ -26,9 +26,12 @@ def curl_version():
     actual_version = [0, 0, 0]
     for build_info_item in gdal.VersionInfo("BUILD_INFO").strip().split("\n"):
         if build_info_item.startswith("CURL_VERSION="):
-            actual_version = [
-                int(x) for x in build_info_item[len("CURL_VERSION=") :].split(".")
-            ]
+            curl_version = build_info_item[len("CURL_VERSION=") :]
+            # Remove potential -rcX postfix.
+            dashrc_pos = curl_version.find("-rc")
+            if dashrc_pos > 0:
+                curl_version = curl_version[0:dashrc_pos]
+            actual_version = [int(x) for x in curl_version.split(".")]
     return actual_version