Fix deb libcairo version, small dropbox.in fixes

 - Ubuntu 14.04 ships with libcairo2 version
   "1.13.0~20140204-0ubuntu1.1", which compares as earlier than
   "1.13.0". Comparing against "1.13" works, though. Remove ".0" from
   all the versions that end with it since that's more likely to be
   what we want.

 - python-gpg was first included in 17.04, not 17.10. Update warning
   to reflect that.

 - Add more logging around error conditions.

dropbox.in

@@ -44,7 +44,7 @@ try:
     gpgme = None
 except ImportError:
     gpg = None
-    # Still support gpgme for now. Remove this once we only support 17.10+.
+    # Still support gpgme for now. Remove this once we only support 17.04+.
     try:
         import gpgme
     except ImportError:
@@ -56,10 +56,10 @@ from posixpath import curdir, sep, pardir, join, abspath, commonprefix
 INFO = u"Dropbox is the easiest way to share and store your files online. Want to learn more? Head to"
 LINK = u"https://www.dropbox.com/"
 WARNING = u"In order to use Dropbox, you must download the proprietary daemon."
-GPG_WARNING = u"Note: python-gpg (python-gpgme for Ubuntu 17.04 and lower) is not installed, we will not be able to verify binary signatures."
+GPG_WARNING = u"Note: python-gpg (python-gpgme for Ubuntu 16.10 and lower) is not installed, we will not be able to verify binary signatures."
 ERROR_CONNECTING = u"Trouble connecting to Dropbox servers. Maybe your internet connection is down, or you need to set your http_proxy environment variable."
 ERROR_SIGNATURE = u"Downloaded binary does not match Dropbox signature, aborting install."
-ERROR_INVALID_DROPBOX = u"Could not run Dropbox. Make sure your computer meets the minimum requirements:\nhttps://www.dropbox.com/help/desktop-web/system-requirements#desktop"
+ERROR_INVALID_DROPBOX = u"Could not start the Dropbox daemon. Make sure your computer meets the minimum requirements:\nhttps://www.dropbox.com/help/desktop-web/system-requirements#desktop"
 
 DOWNLOAD_LOCATION_FMT = "https://www.dropbox.com/download?plat=%s"
 SIGNATURE_LOCATION_FMT = "https://www.dropbox.com/download?plat=%s&signature=1"
@@ -611,6 +611,7 @@ else:
                     break
                 setprogress(DOWNLOADING, progress)
         except Exception:
+            traceback.print_exc()
             FatalVisibleError(ERROR_CONNECTING)
         else:
             setprogress(DOWNLOADING, 1.0)
@@ -621,8 +622,10 @@ else:
             for name, i, total in download.unpack():
                 setprogress(UNPACKING, float(i)/total)
         except SignatureVerifyError:
+            traceback.print_exc()
             FatalVisibleError(ERROR_SIGNATURE)
         except Exception:
+            traceback.print_exc()
             FatalVisibleError(ERROR_CONNECTING)
         else:
             setprogress(UNPACKING, 1.0)

generate-deb.sh

@@ -419,20 +419,28 @@ debian/tmp/usr/*
 
 EOF
 
+# NOTE: When updating dependencies, make sure to test the package on
+# the minimum and maximum supported versions for each distro. In
+# particular, debian version ordering can be tricky. E.g.
+# "1.3.0~somestring" is considered lower than "1.3.0" since usually
+# the "~" is appended to denote a beta version.
+#
+# For more info, see: https://askubuntu.com/a/229749
+
 cat > debian/control <<EOF
 Source: dropbox
 Section: gnome
 Priority: optional
 Maintainer: Dropbox <support@dropbox.com>
-Build-Depends: cdbs, debhelper (>= 9), build-essential, libnautilus-extension-dev (>= 3.10.1), libglib2.0-dev (>= 2.40.0), python-gtk2 (>= 2.24.0), python-docutils
+Build-Depends: cdbs, debhelper (>= 9), build-essential, libnautilus-extension-dev (>= 3.10.1), libglib2.0-dev (>= 2.40), python-gtk2 (>= 2.24), python-docutils
 Standards-Version: 3.9.4.0
 
 Package: dropbox
 Replaces: nautilus-dropbox
 Breaks: nautilus-dropbox
 Provides: nautilus-dropbox
 Architecture: any
-Depends: procps, python-gtk2 (>= 2.24.0), python (>= 2.7), \${python:Depends}, \${misc:Depends}, libatk1.0-0 (>= 2.10.0), libc6 (>= 2.19), libcairo2 (>= 1.13.0), libglib2.0-0 (>= 2.40.0), libgtk2.0-0 (>= 2.24.23), libpango1.0-0 (>= 1.36.3), lsb-release
+Depends: procps, python-gtk2 (>= 2.24), python (>= 2.7), \${python:Depends}, \${misc:Depends}, libatk1.0-0 (>= 2.10), libc6 (>= 2.19), libcairo2 (>= 1.13), libglib2.0-0 (>= 2.40), libgtk2.0-0 (>= 2.24.23), libpango1.0-0 (>= 1.36.3), lsb-release
 Suggests: nautilus (>= 3.10.1), python-gpg (>= 1.8.0)
 Homepage: https://www.dropbox.com/
 Description: cloud synchronization engine - CLI and Nautilus extension